Led tube lamp

ABSTRACT

An LED tube lamp is disclosed. An installation detection circuit is configured in the LED tube lamp configured to receive an external driving signal. The installation detection circuit is configured to detect during one or more pulse signals whether the LED tube lamp is properly installed on a lamp socket, based on detecting a signal generated from the external driving signal. The installation detection circuit includes a switch circuit coupled to the pulse generating circuit, wherein the one or more pulse signals control turning on and off of the switch circuit. The installation detection circuit is further configured to: when it is detected during one or more pulse signals that the LED tube lamp is not properly installed on the lamp socket, control the switch circuit to remain in an off state to cause a power loop of the LED tube lamp to be open; and when it is detected during one or more pulse signals that the LED tube lamp is properly installed on the lamp socket, control the switch circuit to remain in a conducting state to cause the power loop of the LED tube lamp to maintain a conducting state.

RELATED APPLICATIONS

This application is a Continuation-In-Part application of U.S. patentapplication Ser. No. 15/626,238, filed on Jun. 19, 2017, which is aContinuation application of U.S. patent application Ser. No. 15/373,388,filed on Dec. 8, 2016, which is a Continuation-In-Part application ofU.S. patent application Ser. No. 15/339,221, filed on Oct. 31, 2016,U.S. patent application Ser. No. 15/211,813, filed on Jul. 15, 2016,U.S. patent application Ser. No. 15/084,483, filed on Mar. 30, 2016, andU.S. patent application Ser. No. 15/065,892, filed on Mar. 10, 2016.U.S. patent application Ser. No. 15/339,221 is also aContinuation-In-Part application of U.S. patent application Ser. No.15/210,989, filed on Jul. 15, 2016, which is a Continuation-In-Partapplication of U.S. patent application Ser. No. 15/066,645, filed onMar. 10, 2016, which is a Continuation-In-Part application of U.S.patent application Ser. No. 14/865,387, filed on Sep. 25, 2015, thedisclosure of each of which is incorporated in its entirety by referenceherein. U.S. patent application Ser. No. 15/210,989, filed on Jul. 15,2016 is also a Continuation-In-Part application of U.S. patentapplication Ser. No. 15/205,011, filed on Jul. 8, 2016, which is aContinuation-In-Part application of U.S. patent application Ser. No.15/150,458, filed on May 10, 2016, which is a Continuation-In-Part Ser.No. 14/865,387, filed on Sep. 25, 2015, the disclosure of each of whichis incorporated in its entirely by reference herein. U.S. patentapplication Ser. No. 15/211,813 is also a Continuation-In-Partapplication of U.S. patent application Ser. No. 15/150,458, filed on May10, 2016, which is a Continuation-In-Part application of U.S. patentapplication Ser. No. 14/865,387, filed on Sep. 25, 2015. U.S. patentapplication Ser. No. 15/084,483, filed on Mar. 30, 2016, is also aContinuation-In-Part application of U.S. patent application Ser. No.14/865,387, filed on Sep. 25, 2015. U.S. patent application Ser. No.15/065,892, filed on Mar. 10, 2016, is also a Continuation-In-Partapplication of U.S. patent application Ser. No. 14/865,387, filed onSep. 25, 2015. U.S. patent application Ser. No. 14/865,387, filed onSep. 25, 2015 claims priority under 35 U.S.C. 119(e) to Chinese PatentApplications No.: CN 201410507660.9 filed on 2014 Sep. 28; CN201410508899.8 filed on 2014 Sep. 28; CN 201510104823.3 filed on 2015Mar. 10; CN 201510134586.5 filed on 2015 Mar. 26; CN 201510133689.xfiled on 2015 Mar. 25; CN 201510155807.7 filed on 2015 Apr. 3; CN201510193980.6 filed on 2015 Apr. 22; CN 201510284720.x filed on 2015May 29; CN 201510338027.6 filed on 2015 Jun. 17; CN 201510373492.3 filedon 2015 Jun. 26; CN 201510364735.7 filed on 2015 Jun. 26; CN201510378322.4 filed on 2015 Jun. 29; CN 201510406595.5 filed on 2015Jul. 10; CN 201510486115.0 filed on 2015 Aug. 8; CN 201510428680.1 filedon 2015 Jul. 20; CN 201510557717.0 filed on 2015 Sep. 6; CN201510595173.7 filed on 2015 Sep. 18, the disclosures of each of whichare incorporated herein in their entirety by reference.

In addition, U.S. patent application Ser. No. 15/066,645, from whichU.S. patent application Ser. No. 15/210,989 claims priority as aContinuation-In-Part also claims priority under 35 U.S.C. 119(e) toChinese Patent Applications Nos.: CN 201510530110.3 filed on 2015 Aug.26; CN 201510499512.1 filed on 2015 Aug. 14; CN 201510448220.5 filed on2015 Jul. 27; and CN 201510645134.3 filed on 2015 Oct. 8, thedisclosures of each of which are incorporated herein in their entiretyby reference.

In addition, U.S. patent application Ser. No. 15/205,011, from whichU.S. patent application Ser. No. 15/210,989 claims priority as aContinuation-in-Part also claims priority under 35 U.S.C. 119(e) toChinese Patent Application Nos.: CN 201610327806.0, filed on May 18,2016; and CN 201610420790.8, filed on Jun. 14, 2016, the disclosures ofeach of which are incorporated herein in their entirety by reference.

In addition, U.S. patent application Ser. No. 15/210,989 also claimspriority under 35 U.S.C. 119(e) to Chinese Patent Application Nos.: CN201510848766.X, filed on Nov. 27, 2015; CN 201510903680.2, filed on Dec.9, 2015; CN 201610132513.7, filed on Mar. 9, 2016; CN 201610142140.1,filed on Mar. 14, 2016; and CN 201610452437.8, filed on Jun. 20, 2016,the disclosures of each of which are incorporated herein in theirentirety by reference. In addition, U.S. patent application Ser. No.15/210,989 also claims priority under 35 U.S.C. 119(e) to Chinese PatentApplication Nos.: CN 201510530110.3, filed on Aug. 26, 2015; CN201510499512.1, filed on Aug. 14, 2015; CN 201510617370.4, filed on Sep.25, 2015; CN 201510645134.3, filed on Oct. 8, 2015; CN 201510726365.7,filed on Oct. 30, 2015; CN 201610044148.4, filed on Jan. 22, 2016; CN201610051691.7, filed on Jan. 26, 2016; CN 201610085895.2, filed on Feb.15, 2016; CN 201610087627.4, filed on Feb. 16, 2016; CN 201610281812.7,filed on Apr. 29, 2016; CN 201510705222.8, filed on Oct. 27, 2015; CN201610050944.9, filed on Jan. 26, 2016; CN 201610098424.5, filed on Feb.23, 2016; and CN 201610120993.5, filed on Mar. 3, 2016, the disclosuresof each of which are incorporated herein by reference in their entirety.

In addition, U.S. patent application Ser. No. 15/339,221 also claimspriority under 35 U.S.C. 119(e) to Chinese Patent Application No.: CN201610876593.7, filed on Oct. 8, 2016, the entire contents of which areincorporated herein by reference.

In addition, U.S. patent application Ser. No. 15/373,388 claims priorityunder 35 U.S.C. 119(e) to Chinese Patent Application No.: CN201610878349.4, filed on Oct. 8, 2016; CN 201610955338.1, filed on Oct.27, 2016; CN 201610955342.8, filed on Oct. 27, 2016; CN 201610975119.X,filed on Nov. 3, 2016; CN 201611057357.9, filed on November 25; CN201610177706.4, filed on Mar. 25, 2016; and CN 201610890527.5, filed onOct. 12, 2016, the disclosures of each of which are incorporated hereinby reference in their entirety.

This application also claims priority under 35 U.S.C. 119(e) to ChinesePatent Application No.: CN 201710036966.4, filed on Jan. 19, 2017; CN201710170620.3, filed on Mar. 21, 2017; CN 201710158971.2, filed on Mar.16, 2017; CN 201710258874.0, filed on Apr. 19, 2017; CN 201710295599.X,filed on Apr. 28, 2017; and CN 201710591551.3, filed on Jul. 19, 2017,the disclosures of each of which are incorporated herein by reference intheir entirety.

TECHNICAL FIELD

The disclosed embodiments relate to the features of light emitting diode(LED) lighting. More particularly, the disclosed embodiments describevarious improvements for LED tube lamps.

BACKGROUND

LED lighting technology is rapidly developing to replace traditionalincandescent and fluorescent lighting. LED tube lamps are mercury-freein comparison with fluorescent tube lamps that need to be filled withinert gas and mercury. Thus, it is not surprising that LED tube lampsare becoming a highly desired illumination option among differentavailable lighting systems used in homes and workplaces, which used tobe dominated by traditional lighting options such as compact fluorescentlight bulbs (CFLs) and fluorescent tube lamps. Benefits of LED tubelamps include improved durability and longevity and far less energyconsumption. Therefore, when taking into account all factors, they wouldtypically be considered as a cost effective lighting option.

Typical LED tube lamps have a lamp tube, a circuit board disposed insidethe lamp tube with light sources being mounted on the circuit board, andend caps accompanying a power supply provided at two ends of the lamptube with the electricity from the power supply transmitting to thelight sources through the circuit board. However, existing LED tubelamps have certain drawbacks. For example, the typical circuit board isrigid and allows the entire lamp tube to maintain a straight tubeconfiguration when the lamp tube is partially ruptured or broken, andthis gives the user a false impression that the LED tube lamp remainsusable and is likely to cause the user to be electrically shocked uponhandling or installation of the LED tube lamp.

Conventional circuit design of LED tube lamps typically doesn't providesuitable solutions for complying with relevant certification standards.For example, since there are usually no electronic components in afluorescent lamp, it's fairly easy for a fluorescent lamp to becertified under EMI (electromagnetic interference) standards and safetystandards for lighting equipment as provided by UnderwritersLaboratories (UL). However, there are a considerable number ofelectronic components in an LED tube lamp, and therefore considerationof the impacts caused by the layout (structure) of the electroniccomponents is important, resulting in difficulties in complying withsuch standards.

Further, the driving of an LED uses a DC driving signal, but the drivingsignal for a fluorescent lamp is a low-frequency, low-voltage AC signalas provided by an AC powerline, a high-frequency, high-voltage AC signalprovided by a ballast, or even a DC signal provided by a battery foremergency lighting applications. Since the voltages and frequencyspectrums of these types of signals differ significantly, simplyperforming a rectification to produce the required DC driving signal inan LED tube lamp may not achieve the LED tube lamp's compatibility withtraditional driving systems of a fluorescent lamp.

Currently, LED tube lamps used to replace traditional fluorescentlighting devices can be primarily categorized into two types. One is forballast-compatible LED tube lamps, e.g., T-LED lamp, which directlyreplaces fluorescent tube lamps without changing any circuit on thelighting device; and the other one is for ballast by-pass LED tubelamps, which omit traditional ballast on their circuit and directlyconnect the commercial electricity to the LED tube lamp. The latter LEDtube lamp is suitable for the new surroundings in fixtures with newdriving circuits and LED tube lamps. The ballast-compatible LED tubelamp is also known as “Type-A” LED tube lamp, and the ballast by-passLED tube lamp provided with a lamp driving circuit is also known as a“Type-B” LED tube lamp. In the prior art, when a Type-B LED tube lamphas an architecture with dual-end power supply and one end cap thereofis inserted into a lamp socket but the other is not, since the lampsocket corresponding to the Type-B LED tube lamp is configured todirectly receive the commercial electricity without passing through aballast, an electric shock situation could take place for the usertouching the metal or conductive part of the end cap which has not beeninserted into the lamp socket. In addition, due to the frequency of thevoltage provided from the ballast being much higher than the voltagedirectly provided from the commercial electricity/AC mains, the skineffect occurs when the leakage current is generated in the Type-A LEDtube lamp, and thus the human body would not be harmed by the leakagecurrent.

Therefore, since the Type-B LED tube lamp has higher risk of electricshock/hazard, compared to the Type-A, the Type B-LED tube lamp isrequested to have extremely low leakage current for meeting the strictrequirements in the safety certification standard (e.g., UL, CE, GS).

Due to the above technical issues, even many well-known internationalluminaries and LED lamps manufacturers also strand at the bottleneck ondevelopment of the ballast by-pass/Type-B LED tuba lamps having dual-endpower supply structure. Taking GE lighting corporation for the example,according to the marketing material titled “Considering LED tubes”published on Jul. 8, 2014, and the marketing material titled“Dollars&Sense: Type-B LED Tubes” published on Oct. 21, 2016, GElighting corporation asserts, over and over again, that the drawback ofthe risk of electric shock that occurs in the Type-B LED tube lampcannot be overcome, and thus GE lighting corporation would not performfurther product commercialization and sales consideration.

In the prior art, a solution of disposing a mechanical structure on theend cap for preventing electric shock is proposed. In this electricshock protection design, the connection between the external power andthe internal circuit of the tube lamp can be cut off or established bythe mechanical component's interaction/shifting when a user installs thetube lamp, so as to achieve the electric shock protection.

SUMMARY

It's specially noted that the present disclosure may actually includeone or more inventions claimed currently or not yet claimed, and foravoiding confusion due to unnecessarily distinguishing between thosepossible inventions at the stage of preparing the specification, thepossible plurality of inventions herein may be collectively referred toas “the (present) invention” herein.

Various embodiments are summarized in this section, and may be describedwith respect to the “present invention,” which terminology is used todescribe certain presently disclosed embodiments, whether claimed ornot, and is not necessarily an exhaustive description of all possibleembodiments, but rather is merely a summary of certain embodiments.Certain of the embodiments described below as various aspects of the“present invention” can be combined in different manners to form an LEDtube lamp or a portion thereof.

The present disclosure provides a novel LED tube lamp, and aspectsthereof.

According to certain embodiments, a ballast by-pass LED tube lamp isprovided. The ballast by-pass LED tube lamp has at least two externalconnection terminals connected to the opposite sides of the ballastby-pass LED tube lamp. The ballast by-pass LED tube lamp includes adriving circuit, an LED module, a current limiting circuit and anelectric shock detection circuit. The driving circuit, electricallyconnected to the external connection terminals for receiving an externaldriving signal and configured to convert the external driving signalinto a lamp driving signal, wherein the external driving signal has afrequency substantially equal to 50 Hz or 60 Hz. The LED module,electrically connected to the driving circuit for receiving the lampdriving signal. The current limiting circuit, electrically connectedbetween the external connection terminals and the LED module, andconfigured to limit a current flowing through the external connectionterminals and the LED module to less than a predetermined value whenbeing enabled and conduct a current above the predetermined value whenbeing disabled. The electric shock detection circuit, configured totemporarily turn on a detection path of the ballast by-pass LED tubelamp for 10 μs to 30 μs and detect an equivalent impedance of thedetection path being turned on. The electric shock detection circuitcontrols the enable/disable state of the current limiting circuitaccording to the equivalent impedance.

According to certain embodiments, a ballast by-pass LED tube lamp isprovided. The ballast by-pass LED tube lamp includes a lamp tube, twoend caps, a power supply module and an LED module. The end caps arerespectively disposed on opposite sides of the lamp tube. Each end caphas an external connection terminal for receiving an external drivingsignal having a frequency substantially equal to 50 Hz or 60 Hz. Thepower supply module, electrically connected to the external connectionterminals and configured to generate a lamp driving signal based on theexternal driving signal. The LED module, disposed in the lamp tube andelectrically connected to the power supply module for receiving the lampdriving signal. The power supply module includes a current limitingcircuit and an electric shock detection circuit. The current limitingcircuit is electrically connected between at least one of the externalconnection terminals and the LED module and configured to limit acurrent flowing through the external connection terminals and the LEDmodule to less than a predetermined value when being enabled and toconduct a current above the predetermined value when being disabled. Theelectric shock detection circuit, configured to detect a signal on adetection path of the ballast by-pass LED tube lamp and control theenable/disable state of the current limiting circuit according to adetection result. At least some electronic components of the powersupply module are connected via a power circuit board, and the powercircuit board is disposed in at least one of the end caps parallel to anaxial direction of the lamp tube.

According to certain embodiments, a DC-to-DC power converter withleakage current protection is provided. The DC-to-DC power converter hasan input side and an output side and includes a constant currentcontroller, a power switch, a conversion circuit, a feedback circuit anda detection circuit. The constant current controller is configured togenerate a lighting control signal having a pulse waveform. The powerswitch is electrically connected to the constant current controller andconfigured to be switched according to the lighting control signal. Theconversion circuit is electrically connected to the power switch andconfigured to absorb and release power received from the input side inresponse to the switching state of the power switch so as to generate adriving signal at the output side. The feedback circuit is configured togenerate a feedback signal by sampling a signal on at least one of theinput side and the output side and to transmit the feedback signal tothe constant current controller. Under an installation detection mode,the constant current controller outputs the lighting control signal withat least one first pulse and determines whether to enter a normaldriving mode according to the installation detection signal. Under thenormal driving mode, the constant current controller outputs thelighting control signal with a plurality of second pulses and modulatesthe second pulses according to the feedback signal.

BRIEF DESCRIPTION OF THE FIGURES

FIGS. 1A-1C are plane cross-sectional views schematically illustratingan LED tube lamp including an LED light strip that is a bendable circuitsheet with ends thereof passing across the transition region of the lamptube of the LED tube lamp to be connected to a power supply according tosome exemplary embodiments;

FIG. 2 is a plane cross-sectional view schematically illustrating abi-layered structure of a bendable circuit sheet of an LED light stripof an LED tube lamp according to some exemplary embodiments;

FIG. 3A is a perspective view schematically illustrating a soldering padof a bendable circuit sheet of an LED light strip for a solderconnection with a power supply of an LED tube lamp according to someexemplary embodiments;

FIG. 3B is a block diagram illustrating leads that are disposed betweentwo end caps of an LED tube lamp according to some exemplaryembodiments;

FIG. 4A is a perspective view of a bendable circuit sheet and a printedcircuit board of a power supply soldered to each other according to someexemplary embodiments;

FIGS. 4B, 4C, and 4D are diagrams of a soldering process of the bendablecircuit sheet and the printed circuit board of the power supply of FIG.4A in accordance with an exemplary embodiment;

FIG. 4E is a schematic structure of freely extending portion of a lightstrip according to some exemplary embodiments;

FIG. 4F is a cross-sectional view of a light strip along axis Z to Z1according to some exemplary embodiments;

FIG. 5 is a perspective view schematically illustrating a circuit boardassembly composed of a bendable circuit sheet of an LED light strip anda printed circuit board of a power supply according to some exemplaryembodiments;

FIG. 6 is a perspective view schematically illustrating anotherarrangement of a circuit board assembly, according to some exemplaryembodiments;

FIG. 7 is a perspective view schematically illustrating a bendablecircuit sheet of an LED light strip formed with two conductive wiringlayers according to some exemplary embodiments;

FIG. 8A is a block diagram of an exemplary power supply system for anLED tube lamp according to some exemplary embodiments;

FIG. 8B is a block diagram of an exemplary power supply system for anLED tube lamp according to some exemplary embodiments;

FIG. 8C is a block diagram of an exemplary power supply system for anLED tube lamp according to some exemplary embodiments;

FIG. 8D is a block diagram of an exemplary LED lamp according to someexemplary embodiments;

FIG. 8E is a block diagram of an exemplary LED lamp according to someexemplary embodiments;

FIG. 8F is a block diagram of an exemplary LED lamp according to someexemplary embodiments;

FIG. 8G is a block diagram of a connection configuration between an LEDlamp and an external power source according to some exemplaryembodiments;

FIG. 9A-9F are schematic diagrams of exemplary rectifying circuitsaccording to some exemplary embodiments;

FIGS. 10A-10C are block diagrams of exemplary filtering circuitsaccording to some exemplary embodiments;

FIGS. 11A-11B are schematic diagrams of exemplary LED modules accordingto some exemplary embodiments;

FIGS. 11C-11I, 11K are plan views of a circuit layout of an LED moduleaccording to some exemplary embodiments;

FIG. 11J is a schematic view of a power pad according to an exemplaryembodiment.

FIG. 12A is a block diagram of an exemplary power supply module in anLED lamp according to some exemplary embodiments;

FIG. 12B is a block diagram of a driving circuit according to someexemplary embodiments;

FIGS. 12C-12F are signal waveform diagrams of exemplary driving circuitsaccording to some exemplary embodiments;

FIGS. 12G-12J are schematic diagrams of exemplary driving circuitsaccording to some exemplary embodiments;

FIG. 13A is a block diagram of an exemplary power supply module in anLED tube lamp according to some exemplary embodiments;

FIG. 13B is a schematic diagram of an over-voltage protection (OVP)circuit according to some exemplary embodiments;

FIG. 14A is a block diagram of an exemplary power supply module in anLED tube lamp according to some exemplary embodiments;

FIG. 14B is a block diagram of an exemplary power supply module in anLED tube lamp according to some exemplary embodiments;

FIG. 14C is a schematic diagram of an auxiliary power module accordingto some exemplary embodiments;

FIG. 14D is a block diagram of an exemplary power supply module of anLED tube lamp according to some exemplary embodiments;

FIG. 14E is a block diagram of an exemplary auxiliary power moduleaccording to some exemplary embodiments;

FIG. 14F is a block diagram of an exemplary power supply module in anLED tube lamp according to some exemplary embodiments;

FIGS. 14G-14H are block diagrams of exemplary auxiliary power modulesaccording to some exemplary embodiments;

FIGS. 14I-14J are schematic structures of an auxiliary power moduledisposed in an LED tube lamp according to some exemplary embodiments;

FIGS. 14K-14M are block diagrams of LED lighting systems according tosome exemplary embodiments;

FIG. 15A is a block diagram of an LED tube lamp according to someexemplary embodiments;

FIG. 15B is a block diagram of an installation detection moduleaccording to some exemplary embodiments;

FIG. 15C is a schematic detection pulse generating module according tosome exemplary embodiments;

FIG. 15D is a schematic detection determining circuit according to someexemplary embodiments;

FIG. 15E is a schematic detection result latching circuit according tosome exemplary embodiments;

FIG. 15F is a schematic switch circuit according to some exemplaryembodiments;

FIG. 15G is a block diagram of an installation detection moduleaccording to some exemplary embodiments;

FIG. 15H is a schematic detection pulse generating module according tosome exemplary embodiments;

FIG. 15I is a schematic detection result latching circuit according tosome exemplary embodiments;

FIG. 15J is a schematic switch circuit according to some exemplaryembodiments; and

FIG. 15K is a schematic detection determining circuit according to someexemplary embodiments.

FIG. 15L is a block diagram of an installation detection moduleaccording to some exemplary embodiments;

FIG. 15M is an internal circuit block diagram of an integrated controlmodule according to some exemplary embodiments;

FIG. 15N is a schematic pulse generating auxiliary circuit according tosome exemplary embodiments;

FIG. 15O is a schematic detection determining auxiliary circuitaccording to some exemplary embodiments;

FIG. 15P is a schematic switch circuit according to some exemplaryembodiments;

FIG. 15Q is an internal circuit block diagram of a three-terminal switchdevice according to some exemplary embodiments;

FIG. 15R is a schematic signal processing unit according to someexemplary embodiments;

FIG. 15S is a schematic signal generating unit according to someexemplary embodiments;

FIG. 15T is a schematic signal capturing unit according to someexemplary embodiments;

FIG. 15U is a schematic switch unit according to some exemplaryembodiments;

FIG. 15V is a schematic internal power detection unit according to someexemplary embodiments;

FIG. 15W a block diagram of an installation detection module accordingto some exemplary embodiments;

FIG. 15X is a block diagram of a detection path circuit according tosome exemplary embodiments;

FIG. 15Y is a schematic diagram illustrating an installation state of anLED tube lamp according to some exemplary embodiments;

FIG. 16A is a block diagram of an exemplary power supply module in anLED tube lamp according to some exemplary embodiments;

FIG. 16B is a schematic diagram of an exemplary driving circuitaccording to some exemplary embodiments;

FIGS. 16C-16D are block diagrams of exemplary power supply modulesaccording to some exemplary embodiments; and

FIGS. 17A-17C are signal waveform diagrams of exemplary power supplymodules according to some exemplary embodiments.

DETAILED DESCRIPTION

The present disclosure provides a novel LED tube lamp. The presentdisclosure will now be described in the following embodiments withreference to the drawings. The following descriptions of variousembodiments of this invention are presented herein for purpose ofillustration and giving examples only. It is not intended to beexhaustive or to be limited to the precise form disclosed. These exampleembodiments are just that—examples—and many implementations andvariations are possible that do not require the details provided herein.It should also be emphasized that the disclosure provides details ofalternative examples, but such listing of alternatives is notexhaustive. Furthermore, any consistency of detail between variousexamples should not be interpreted as requiring such detail—it isimpracticable to list every possible variation for every featuredescribed herein. The language of the claims should be referenced indetermining the requirements of the invention.

In the drawings, the size and relative sizes of components may beexaggerated for clarity. Like numbers refer to like elements throughout.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. As used herein, the term “and/or” includes any and allcombinations of one or more of the associated listed items and may beabbreviated as “/”.

It will be understood that, although the terms first, second, third etc.may be used herein to describe various elements, components, regions,layers, or steps, these elements, components, regions, layers, and/orsteps should not be limited by these terms. Unless the context indicatesotherwise, these terms are only used to distinguish one element,component, region, layer, or step from another element, component,region, or step, for example as a naming convention. Thus, a firstelement, component, region, layer, or step discussed below in onesection of the specification could be termed a second element,component, region, layer, or step in another section of thespecification or in the claims without departing from the teachings ofthe present invention. In addition, in certain cases, even if a term isnot described using “first,” “second,” etc., in the specification, itmay still be referred to as “first” or “second” in a claim in order todistinguish different claimed elements from each other.

It will be further understood that the terms “comprises” and/or“comprising,” or “includes” and/or “including” when used in thisspecification, specify the presence of stated features, regions,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof.

It will be understood that when an element is referred to as being“connected” or “coupled” to or “on” another element, it can be directlyconnected or coupled to or on the other element or intervening elementsmay be present. In contrast, when an element is referred to as being“directly connected” or “directly coupled” to another element, there areno intervening elements present. Other words used to describe therelationship between elements should be interpreted in a like fashion(e.g., “between” versus “directly between,” “adjacent” versus “directlyadjacent,” etc.). However, the term “contact,” as used herein refers todirect connection (i.e., touching) unless the context indicatesotherwise.

Embodiments described herein will be described referring to plane viewsand/or cross-sectional views by way of ideal schematic views.Accordingly, the exemplary views may be modified depending onmanufacturing technologies and/or tolerances. Therefore, the disclosedembodiments are not limited to those shown in the views, but includemodifications in configuration formed on the basis of manufacturingprocesses. Therefore, regions exemplified in figures may have schematicproperties, and shapes of regions shown in figures may exemplifyspecific shapes of regions of elements to which aspects of the inventionare not limited.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper” and the like, may be used herein for ease of description todescribe one element's or feature's relationship to another element(s)or feature(s) as illustrated in the figures. It will be understood thatthe spatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the term “below” can encompass both an orientation ofabove and below. The device may be otherwise oriented (rotated 90degrees or at other orientations) and the spatially relative descriptorsused herein interpreted accordingly.

Terms such as “same,” “equal,” “planar,” or “coplanar,” as used hereinwhen referring to orientation, layout, location, shapes, sizes, amounts,or other measures do not necessarily mean an exactly identicalorientation, layout, location, shape, size, amount, or other measure,but are intended to encompass nearly identical orientation, layout,location, shapes, sizes, amounts, or other measures within acceptablevariations that may occur, for example, due to manufacturing processes.The term “substantially” may be used herein to emphasize this meaning,unless the context or other statements indicate otherwise. For example,items described as “substantially the same,” “substantially equal,” or“substantially planar,” may be exactly the same, equal, or planar, ormay be the same, equal, or planar within acceptable variations that mayoccur, for example, due to manufacturing processes.

Terms such as “about” or “approximately” may reflect sizes,orientations, or layouts that vary only in a small relative manner,and/or in a way that does not significantly alter the operation,functionality, or structure of certain elements. For example, a rangefrom “about 0.1 to about 1” may encompass a range such as a 0%-5%deviation around 0.1 and a 0% to 5% deviation around 1, especially ifsuch deviation maintains the same effect as the listed range.

Terms such as “transistor”, used herein may include, for example, afield-effect transistor (FET) of any appropriate type such as N-typemetal-oxide-semiconductor field-effect transistor (MOSFET), P-typeMOSFET, GaN FET, SiC FET, bipolar junction transistor (BJT), DarlingtonBJT, heterojunction bipolar transistor (HBT), etc.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure belongs. It willbe further understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and/orthe present application, and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein.

As used herein, items described as being “electrically connected” areconfigured such that an electrical signal can be passed from one item tothe other. Therefore, a passive electrically conductive component (e.g.,a wire, pad, internal electrical line, etc.) physically connected to apassive electrically insulative component (e.g., a prepreg layer of aprinted circuit board, an electrically insulative adhesive connectingtwo devices, an electrically insulative underfill or mold layer, etc.)is not electrically connected to that component. Moreover, items thatare “directly electrically connected,” to each other are electricallyconnected through one or more passive elements, such as, for example,wires, pads, internal electrical lines, etc. As such, directlyelectrically connected components do not include components electricallyconnected through active elements, such as transistors or diodes, orthrough capacitors. Directly electrically connected elements may bedirectly physically connected and directly electrically connected.

Components described as thermally connected or in thermal communicationare arranged such that heat will follow a path between the components toallow the heat to transfer from the first component to the secondcomponent. Simply because two components are part of the same device orboard does not make them thermally connected. In general, componentswhich are heat-conductive and directly connected to otherheat-conductive or heat-generating components (or connected to thosecomponents through intermediate heat-conductive components or in suchclose proximity as to permit a substantial transfer of heat) will bedescribed as thermally connected to those components, or in thermalcommunication with those components. On the contrary, two componentswith heat-insulative materials therebetween, which materialssignificantly prevent heat transfer between the two components, or onlyallow for incidental heat transfer, are not described as thermallyconnected or in thermal communication with each other. The terms“heat-conductive” or “thermally-conductive” do not apply to any materialthat provides incidental heat conduction, but are intended to refer tomaterials that are typically known as good heat conductors or known tohave utility for transferring heat, or components having similar heatconducting properties as those materials.

Embodiments may be described, and illustrated in the drawings, in termsof functional blocks, units and/or modules. Those skilled in the artwill appreciate that these blocks, units and/or modules are physicallyimplemented by electronic (or optical) circuits such as logic circuits,discrete components, analog circuits, hard-wired circuits, memoryelements, wiring connections, and the like, which may be formed usingsemiconductor-based fabrication techniques or other manufacturingtechnologies. In the case of the blocks, units and/or modules beingimplemented by microprocessors or similar, they may be programmed usingsoftware (e.g., microcode) to perform various functions discussed hereinand may optionally be driven by firmware and/or software. Alternatively,each block, unit and/or module may be implemented by dedicated hardware,or as a combination of dedicated hardware to perform some functions anda processor (e.g., one or more programmed microprocessors and associatedcircuitry) to perform other functions. Also, each block, unit and/ormodule of the embodiments may be physically separated into two or moreinteracting and discrete blocks, units and/or modules. Further, theblocks, units and/or modules of the various embodiments may bephysically combined into more complex blocks, units and/or modules.

If any terms in this application conflict with terms used in anyapplication(s) from which this application claims priority, or termsincorporated by reference into this application or the application(s)from which this application claims priority, a construction based on theterms as used or defined in this application should be applied.

It should be noted that, the following description of variousembodiments of the present disclosure is described herein in order toclearly illustrate the inventive features of the present disclosure.However, it is not intended that various embodiments can only beimplemented alone. Rather, it is contemplated that various of thedifferent embodiments can be and are intended to be used together in afinal product, and can be combined in various ways to achieve variousfinal products. Thus, people having ordinary skill in the art maycombine the possible embodiments together or replace thecomponents/modules between the different embodiments according to designrequirements. The embodiments taught herein are not limited to the formdescribed in the following examples, any possible replacement andarrangement between the various embodiments are included.

Applicant's prior U.S. patent application Ser. No. 14/724,840 (US PGPUbNo. 2016/0091156, the disclosure of which is incorporated herein in itsentirety by reference), as an illustrated example, has addressed certainissues associated with the occurrence of electric shock in using aconventional LED lamp by providing a bendable circuit sheet. Some of theembodiments disclosed in U.S. patent application Ser. No. 14/724,840 canbe combined with one or more of the example embodiments disclosed hereinto further reduce the occurrence of electric shock in using an LED lamp.

FIG. 1A is a plane cross-sectional view schematically illustrating anLED tube lamp including an LED light strip and a power supply moduleaccording to some exemplary embodiments. Referring to FIG. 1A, an LEDtube lamp may include an LED light strip 2 and a power supply 5, inwhich the power supply 5 can be a modularized element, which means thepower supply 5 can be integrated into a single power supply circuit orcan be integrated into several separated power supply circuits. Forexample, in an embodiment, the power supply 5 can be a single unit(i.e., all components of the power supply 5 are disposed on a singlebody/carrier) disposed in one of the end caps at one end of the lamptube. In another embodiment, the power supply 5 can be two separateunits (i.e., the components of the power supply 5 are divided into twoparts) disposed in different end caps at respective ends of the lamptube.

In the embodiment of FIG. 1A, the power supply 5 is illustrated as beingintegrated into one module for example (hereinafter referred to as apower supply module 5) and is disposed in the end cap parallel to theaxial direction cyd of the lamp tube. More specifically, the axialdirection cyd of the lamp tube, which refers to the direction pointed toby the axis of the lamp tube, is perpendicular to the end wall of theend caps. Disposing the power supply module 5 parallel to the axialdirection cyd means the circuit board, with the electronic components ofthe power supply module, is parallel to the axial direction cyd.Therefore, the normal direction of the circuit board is perpendicular tothe axial direction cyd. In certain embodiments, the power supply module5 can be arranged in a position where the axial direction cyd passes, ina position above the axial plane/axial direction cyd, or in a positionbelow the axial plane/axial direction cyd (relative to the figure). Theinvention is not limited thereto.

FIG. 1B is another plane cross-sectional view schematically illustratingan LED tube lamp including an LED light strip and a power supply moduleaccording to some exemplary embodiments. Referring to FIG. 1B, thedifference between the embodiments of FIGS. 1A and 1B is that the powersupply module 5 illustrated in FIG. 1B is disposed in the end capperpendicular to the axial direction cyd of the lamp tube. For example,the power supply module 5 is disposed parallel to the end wall of theend caps. Although the FIG. 1B shows that the electronic components aredisposed on the side facing the interior of the lamp tube, the inventionis not limited thereto. In certain embodiments, the electronic componentcan be disposed on the side facing the end wall of the corresponding endcap. Under these configurations, since at least one opening can beformed in the end wall of the end caps, the heat dissipation effect ofthe electronic components can be improved through the opening.

In addition, due to the power supply module 5 being vertically disposedin the end caps, the space within the end caps can be increased so thatthe power supply module 5 can be further divided into a plurality ofseparated circuit boards as shown in FIG. 1C. FIG. 1C is still anotherplane cross-sectional view schematically illustrating an LED tube lampincluding an LED light strip and a power supply module according to someexemplary embodiments. The difference between the embodiments of FIGS.1B and 1C is that the power supply 5 is formed by two power supplymodules 5 a and 5 b. The power supply modules 5 a and 5 b are disposedin the end cap perpendicular to the axial direction cyd and arearranged, toward to the end wall of the end cap, along the axialdirection cyd. Specifically, power supply modules 5 a and 5 b arerespectively provided with each having an independent circuit board. Thecircuit boards are connected to each other through one or moreelectrical connection means, so that the overall power supply circuittopology is similar to the embodiment illustrated in FIG. 1A or FIG. 1B.According to the configuration of FIG. 1C, the space within the end capscan be more effectively utilized, such that the circuit layout space canbe increased. In some certain embodiments, the electronic componentsgenerating more heat (e.g., the capacitor and the inductor) can bedisposed on the power supply module 5 b, which is close to the end wall,so as to enhance the heat dissipation effect of the electroniccomponents through the opening on the end cap.

In certain embodiments, the circuit boards of the power supply modules 5a and 5 b can be designed as a disk shape structure (not shown). Thedisk-shaped circuit boards are disposed in the same end cap along thesame axis. For example, the maximum outer diameter of the circuit boardsmay be slightly smaller than the inner diameter of the end cap and thenormal direction of the disk plane is substantially parallel to theradial direction of the end cap, so that the disk-shaped circuit boardscan be disposed into the space of the end cap. In certain embodiments,at least a DC-to-DC converter circuit and a conversion control IC (i.e.,lighting control circuit) are disposed on the disk-shaped circuit boardof the power supply module 5 a, and at least a fuse, a EMI module, arectifying circuit and an installation detection module are disposed onthe disk-shaped circuit board of the power supply module 5 b. Thedisk-shaped circuit board of the power supply module 5 b is disposedclose to the side wall of the end cap (in relation to the power supplymodule 5 a and other components of the LED tube lamp) and electricallyconnected to the conduction pins on the end cap. The disk-shaped circuitboards of the power supply modules 5 a and 5 b are electricallyconnected to each other. The disk-shaped circuit board of the powersupply module 5 a is electrically connected to the LED light strip 2.

In certain embodiments, in order to vertically dispose the power supplymodules 5 a and 5 b in the cylindrical end caps and maximize the layoutarea, the circuit boards of the power supply modules 5 a and 5 b canadopt an octagon structure. But other shapes can be used.

For the connection means between the power supply modules 5 a and 5 b,the separate power supply modules 5 a and 5 b can be connected to eachother, for example, through a male plug and a female plug or throughbonding a lead. If the lead is utilized to connect the power supplymodules 5 a and 5 b, the outer layer of the lead can be wrapped with aninsulating sleeve to serve as electrical insulation protection. Inaddition, the power supply modules 5 a and 5 b can also be connectedthrough rivets or solder paste, or bound together by wires.

Referring to FIGS. 1A to 1C, an LED tube lamp may include an LED lightstrip 2. In certain embodiments, the LED light strip 2 may be formedfrom a bendable circuit sheet, for example that may be flexible. Asdescribed further below, the bendable circuit sheet is also described asa bendable circuit board. The LED light strip 2, and for example thebendable circuit sheet, may also be a flexible strip, such as a flexibleor non-rigid tape or a ribbon. The bendable circuit sheet may have endsthereof passing across a transition region of the lamp tube of the LEDtube lamp to be connected to a power supply 5. In some embodiments, theends of the bendable circuit sheet may be connected to a power supply inan end cap of the LED tube lamp. For example, the ends may be connectedin a manner such that a portion of the bendable circuit sheet is bentaway from the lamp tube and passes through the transition region where alamp tube narrows, and such that the bendable circuit sheet verticallyoverlaps part of a power supply within an end cap of the LED tube lamp.

Referring to FIG. 2, to form an LED light strip 2, a bendable circuitsheet includes a wiring layer 2 a with conductive effect. An LED lightsource 202 is disposed on the wiring layer 2 a and is electricallyconnected to the power supply through the wiring layer 2 a. Though onlyone LED light source 202 is shown in FIG. 2, a plurality of LED lightsources 202, as shown in FIG. 1, may be arranged on the LED light strip2. For example, light sources 202 may be arranged in one or more rowsextending along a length direction of the LED light strip 2, which mayextend along a length direction of the lamp tube as illustrated inFIG. 1. The wiring layer with conductive effect, in this specification,is also referred to as a conductive layer. Referring to FIG. 2 again, inone embodiment, the LED light strip 2 includes a bendable circuit sheethaving a conductive wiring layer 2 a and a dielectric layer 2 b that arearranged in a stacked manner. In some embodiments, the wiring layer 2 aand the dielectric layer 2 b may have the same areas or the area of thewiring layer 2 a may slightly be smaller than that of the dielectriclayer 2 b. The LED light source 202 is disposed on one surface of thewiring layer 2 a, the dielectric layer 2 b is disposed on the othersurface of the wiring layer 2 a that is away from the LED light sources202 (e.g., a second, opposite surface from the first surface on whichthe LED light source 202 is disposed). The wiring layer 2 a iselectrically connected to a power supply 5 (as shown in FIG. 1) to carrydirect current (DC) signals. In some embodiments, the surface of thedielectric layer 2 b away from the wiring layer 2 a (e.g., a secondsurface of the dielectric layer 2 b opposite a first surface facing thewiring layer 2 a) is fixed to an inner circumferential surface of a lamptube, for example, by means of an adhesive sheet 4. The portion of thedielectric layer 2 b fixed to the inner circumferential surface of thelamp tube 1 may substantially conform to the shape of the innercircumferential surface of the lamp tube 1. The wiring layer 2 a can bea metal layer or a power supply layer including wires such as copperwires.

A power supply as described herein may include a circuit that convertsor generates power based on a received voltage, in order to supply powerto operate an LED module and the LED light sources 202 of the LED tubelamp. A power supply, as described in connection with power supply 5,may be otherwise referred to as a power conversion module or circuit ora power module. A power conversion module or circuit, or power module,may supply or provide power from external signal(s), such as from an ACpower line or from a ballast, to an LED module and the LED light sources202. For example, a power supply 5 may refer to a circuit that convertsac line voltage to dc voltage and supplies power to the LED or LEDmodule. The power supply 5 may include one or more power componentsmounted thereon for converting and/or generating power.

In some example embodiments, the outer surface of the wiring layer 2 aor the dielectric layer 2 b may be covered with a circuit protectivelayer made of an ink with function of resisting soldering and increasingreflectivity. Alternatively, in other example embodiments, thedielectric layer may be omitted and the wiring layer may be directlybonded to the inner circumferential surface of the lamp tube, and theouter surface of the wiring layer 2 a may be coated with the circuitprotective layer. Whether the wiring layer 2 a has a one-layered, ortwo-layered structure, the circuit protective layer may be adopted. Insome embodiments, the circuit protective layer is disposed only on oneside/surface of the LED light strip 2, such as the surface having theLED light source 202. In some embodiments, the bendable circuit sheet isa one-layered structure made of just one wiring layer 2 a, or atwo-layered structure made of one wiring layer 2 a and one dielectriclayer 2 b, and thus is more bendable or flexible to curl when comparedwith the conventional three-layered flexible substrate (one dielectriclayer sandwiched with two wiring layers). As a result, the bendablecircuit sheet of the LED light strip 2 may be installed in a lamp tubewith a customized shape or non-tubular shape, and fitly mounted to theinner surface of the lamp tube. A bendable circuit sheet closely mountedto the inner surface of the lamp tube is desirable in some cases. Inaddition, using fewer layers of the bendable circuit sheet improves theheat dissipation, lowering the material cost, and is more environmentalfriendly, and provides the opportunity to increase the flexible effect.

Nevertheless, the bendable circuit sheet is not limited to beingone-layered or two-layered; in other embodiments, the bendable circuitsheet may include multiple layers of the wiring layers 2 a and multiplelayers of the dielectric layers 2 b, in which the dielectric layers 2 band the wiring layers 2 a are sequentially stacked in a staggeredmanner, respectively. These stacked layers may be between the outermostwiring layer 2 a (with respect to the inner circumferential surface ofthe lamp tube), which has the LED light source 202 disposed thereon, andthe inner circumferential surface of the lamp tube, and may beelectrically connected to the power supply 5 (as shown in FIG. 1.)Moreover, in some embodiments, the length of the bendable circuit sheet(e.g., the length along a surface of the bendable circuit sheet from oneend of the circuit sheet to a second end of the circuit sheet) (or anaxial projection of the length of the bendable circuit sheet) is greaterthan the length of the lamp tube (or an axial projection of the lengthof the lamp tube), or at least greater than a central portion of thelamp tube between two transition regions (e.g., where the circumferenceof the lamp tube narrows) on either end. For example, the lengthfollowing along the contours of one surface of the bendable circuitsheet (e.g., a top surface of the circuit sheet) may be longer than thelength from one terminal end to an opposite terminal end of the lamptube. Also, a length along a straight line that extends in the samedirection as the direction in which the lamp tube extends, from a firstend of the bendable circuit sheet to a second, opposite end of thebendable circuit sheet, may be longer than the length along the samestraight line of the lamp tube.

Referring to FIG. 7, in one embodiment, an LED light strip 2 includes abendable circuit sheet having in sequence a first wiring layer 2 a, adielectric layer 2 b, and a second wiring layer 2 c. In one example, thethickness of the second wiring layer 2 c (e.g., in a direction in whichthe layers 2 a through 2 c are stacked) is greater than that of thefirst wiring layer 2 a, and the length of the LED light strip 2 (or anaxial projection of the length of the LED light strip 2) is greater thanthat of a lamp tube 1, or at least greater than a central portion of thelamp tube between two transition regions (e.g., where the circumferenceof the lamp tube narrows) on either end. The end region of the LED lightstrip 2 extending beyond the end portion of the lamp tube 1 withouthaving a light source 202 disposed thereon is formed with two separatethrough holes 203 and 204 to respectively electrically communicate thefirst wiring layer 2 a and the second wiring layer 2 c. The throughholes 203 and 204 are not in communication with each other to avoidshort.

In this way, the greater thickness of the second wiring layer 2 c allowsthe second wiring layer 2 c to support the first wiring layer 2 a andthe dielectric layer 2 b, and meanwhile allows the LED light strip 2 tobe mounted onto the inner circumferential surface without being liableto shift or deform, and thus the yield rate of product can be improved.In addition, the first wiring layer 2 a and the second wiring layer 2 care in electrical communication such that the circuit layout of thefirst wiring later 2 a can be extended downward to the second wiringlayer 2 c to reach the circuit layout of the entire LED light strip 2.Moreover, since the circuit layout becomes two-layered, the area of eachsingle layer and therefore the width of the LED light strip 2 can bereduced such that more LED light strips 2 can be put on a productionline to increase productivity.

Furthermore, in some embodiments, the first wiring layer 2 a and thesecond wiring layer 2 c of the end region of the LED light strip 2 thatextends beyond the end portion of the lamp tube 1 without disposition ofthe light source 202 can be used to accomplish the circuit layout of apower supply module so that the power supply module can be directlydisposed on the bendable circuit sheet of the LED light strip 2.

In a case where two ends of the LED light strip 2 are detached from theinner surface of the lamp tube 1 and where the LED light strip 2 isconnected to the power supply 5 via wire-bonding, certain movements insubsequent transportation are likely to cause the bonded wires to break.Therefore, a desirable option for the connection between the LED lightstrip 2 and the power supply 5 (as shown in FIG. 1) could be soldering.Specifically, referring to FIG. 1, the ends of the LED light strip 2including the bendable circuit sheet are arranged to pass over thestrengthened transition region of a lamp tube, and to be directly solderbonded to an output terminal of the power supply 5. This may improveproduct quality by avoiding using wires and/or wire bonding. Asdiscussed herein, a transition region of the lamp tube refers to regionsoutside a central portion of the lamp tube and inside terminal ends ofthe lamp tube. For example, a central portion of the lamp tube may havea constant diameter, and each transition region between the centralportion and a terminal end of the lamp tube may have a changing diameter(e.g., at least part of the transition region may become more narrowmoving in a direction from the central portion to the terminal end ofthe lamp tube).

Referring to FIG. 3A, an output terminal of a printed circuit board ofthe power supply 5 may have soldering pads “a” (as shown in FIG. 1A aswell) provided with an amount of solder (e.g., tin solder) with athickness sufficient to later form a solder joint “g” (or a solder ball“g”). Correspondingly, the ends of the LED light strip 2 may havesoldering pads “b” (as shown in FIG. 1A as well). The soldering pads “a”on the output terminal of the printed circuit board of the power supply5 are soldered to the soldering pads “b” on the LED light strip 2 viathe tin solder on the soldering pads “a”. The soldering pads “a” and thesoldering pads “b” may be face to face during soldering such that theconnection between the LED light strip 2 and the printed circuit boardof the power supply 5 may be the firmest. However, this kind ofsoldering typically includes a thermo-compression head pressing on therear surface of the LED light strip 2 and heating the tin solder, i.e.,the LED light strip 2 intervenes between the thermo-compression head andthe tin solder, and therefore may cause reliability problems. In someembodiments, a through hole may be formed in each of the soldering pads“b” on the LED light strip 2 to allow the soldering pads “b” to overlaythe soldering pads “a” without being face-to-face (e.g., both solderingpads “a” and soldering pads “b” can have exposed surfaces that face thesame direction) and the thermo-compression head directly presses tinsolders on the soldering pads “a” on surface of the printed circuitboard of the power supply 5 when the soldering pads “a” and thesoldering pads “b” are vertically aligned. This example provides asimple process for manufacturing.

Referring again to FIG. 3A, two ends of the LED light strip 2 detachedfrom the inner surface of the lamp tube 1 (as shown in FIG. 7) areformed as freely extending portions 21 (as shown in FIGS. 1A and 7 aswell), while most of the LED light strip 2 is attached and secured topart of the inner surface of the lamp tube to form a fixed portion 22.One of the freely extending portions 21 has the soldering pads “b” asmentioned above. In one embodiment, one end of the freely extendingportion 21 is welded to the power supply module 5, and the other end ofthe freely extending portion 21 is extended and connected, as a whole,to the fixed portion 22 (e.g., is integrally formed with the fixedportion 22). The portions between two ends of the freely extendingportion 21 are not attached to the inner surface of the lamp tube 1,which means the middle section of the freely extending portion 21 issuspended (e.g., is not fixedly held by the lamp tube 1). Uponassembling of the LED tube lamp, the freely extending portions 21 alongwith the soldered connection of the printed circuit board of the powersupply 5 and the LED light strip 2 would be coiled, curled up ordeformed to be fittingly accommodated inside the lamp tube as shown inFIG. 1. When the bendable circuit sheet of the LED light strip 2includes in sequence the first wiring layer 2 a, the dielectric layer 2b, and the second wiring layer 2 c as shown in FIG. 7, the freelyextending portions 21, which are the end regions of the LED light strip2 extending beyond the lamp tube without disposition of the lightsources 202, can be used to accomplish the connection between the firstwiring layer 2 a and the second wiring layer 2 c and arrange the circuitlayout of the power supply 5. As described above, the freely extendingportions 21 may be different from a fixed portion of the LED light strip2 in that the fixed portion may conform to the shape of the innersurface of the lamp tube and may be fixed thereto, while the freelyextending portion 21 may have a shape that does not conform to the shapeof the lamp tube. As shown in FIGS. 1A to 1C, the freely extendingportion 21 may be bent away from the lamp tube. For example, there maybe a space between an inner surface of the lamp tube and the freelyextending portion 21.

In designing the conductive pin or external connection terminal in theLED tube lamp, various arrangements of pins may be provided in one endor both ends of the LED tube lamp according to exemplary embodiments.For example, two pins may be provided in one end and no pins may beprovided on the other end. Alternatively, in some embodiments, two pinsin corresponding ends of two ends of the LED tube lamp, or four pins incorresponding ends of two ends of the LED tube lamp may be provided.When a dual-end power supply between two ends of the LED tube lamp isutilized to provide power to the LED tube lamp, at least one pin of eachend of the LED tube lamp is used to receive the external driving signalfrom the power supply.

FIG. 3B is a block diagram illustrating leads that are disposed betweentwo end caps of an LED tube lamp according to some exemplaryembodiments.

Referring to FIG. 3B, in some embodiments, the LED tube lamp includes alamp tube (not shown in FIG. 3B), end caps (not shown in FIG. 3B), alight strip 2, short circuit boards 253 (also referred to as right endshort circuit board 253 and left end short circuit board 253)respectively provided at two ends of the lamp tube, and an inductiveelement 526. Each of the lamp tube's two ends may have at least one pinor external connection terminal for receiving the external drivingsignal. The end caps are disposed respectively at the two ends of thelamp tube, and (at least partial electronic components of) the shortcircuit boards 253 shown as located respectively at the left and rightends of the lamp tube in FIG. 3B may be disposed respectively in the endcaps. The short circuit boards may be, for example, a rigid circuitboard such as depicted in and described in connection with FIG. 1 andthe various other rigid circuit boards described herein. For example,these circuit boards may include mounted thereon one or more powersupply components for generating and/or converting power to be used tolight the LED light sources on the light strip 2. The light strip 2 isdisposed in the lamp tube and includes an LED module, which includes anLED unit 632.

For an LED tube lamp, such as an 8 ft. 42 W LED tube lamp, to receive adual-end power supply between two ends of the LED tube lamp, two(partial) power supply circuits (each having a power rating of e.g. 21W, 17.5 W, or 12.5 W) are typically disposed respectively in the two endcaps of the lamp tube, and a lead (typically referred to as lead Line,Neutral and Ground) disposed between two end caps of the lamp tube(e.g., between two pins or external connection terminals at respectiveend caps of the lamp tube), connected to the power supply circuitsdisposed on the opposite sides of the light strip and as an input signalline may be needed. The lead Line (also known as the “live wire”) and/orthe lead Neutral (also known as the “neutral wire”) may be disposedalong the light strip that may include, e.g., a bendable circuit sheetor flexible circuit board, for receiving and transmitting an externaldriving signal from the power supply. This lead Line is distinct fromtwo leads typically referred to as LED+ and LED− that are respectivelyconnected to a positive electrode and a negative electrode of an LEDunit in the lamp tube. This lead Line is also distinct from a leadGround (also known as the “earth wire”) which is disposed betweenrespective ground terminals of the LED tube lamp. Because the lead Lineis typically disposed along the light strip, and because parasiticcapacitance(s) (e.g., about 200 pF) may be caused between the lead Lineand the lead LED+ due to their close proximity to each other, some highfrequency signals (not the intended frequency range of signal forsupplying power to the LED module) passing through the lead LED+ will bereflected to the lead Line through the parasitic capacitance(s) and thencan be detected there as undesirable EMI effects. The unfavorable EMIeffects may lower or degrade the quality of power transmission in theLED tube lamp.

Again referring to FIG. 3B, in some embodiments, the right and leftshort circuit boards 253 are electrically connected to the light strip2. In some embodiments, the electrical connection (such as throughsoldering or bond pad(s)) between the short circuit boards 253 and thelight strip 2 may comprise a first terminal (denoted by “L”), a secondterminal (denoted by “+” or “LED+”), a third terminal (denoted by “−” or“LED-”), and a fourth terminal (denoted by “GND” or “ground”). The lightstrip 2 includes the first through fourth terminals at a first end ofthe light strip 2 adjacent to the right end short circuit board 253 nearone end cap of the lamp tube and includes the first through fourthterminals at a second end, opposite to the first end, of the light strip2 adjacent to the left end short circuit board 253 near the other endcap of the lamp tube. The right end short circuit board 253 alsoincludes the first through fourth terminals to respectively connect tothe first through fourth terminals of the light strip 2 at the first endof the light strip 2. The left end short circuit board 253 also includesthe first through fourth terminals to respectively connect to the firstthrough fourth terminals of the light strip 2 at the second end of thelight strip 2. For example, the first terminal L is utilized to connecta lead (typically referred to as Line or Neutral) for connecting both ofthe at least one pin of each of the two ends of the lamp tube; thesecond terminal LED+ is utilized to connect each of the short circuitboards 253 to the positive electrode of the LED unit 632 of the LEDmodule included in the light strip 2. The third terminal LED− isutilized to connect each of the short circuit boards 253 to the negativeelectrode of the LED unit 632 of the LED module included in the lightstrip 2. The fourth terminal GND is utilized to connect to a referencepotential. Preferably and typically, the reference potential is definedas the electrical potential of ground. Therefore, the fourth terminal isutilized for a grounding purpose of the power supply module of the LEDtube lamp.

To address the undesirable EMI effects mentioned above caused byparasitic capacitance(s) between the lead Line and the lead LED+,inductive element 526 disposed in the lead Ground serves to reduce orprevent the EMI effects by blocking the forming of a complete circuitbetween the lead LED+ and the Ground lead for the high frequency signalsmentioned above to pass through, since at these high frequenciesinductive element 526 behaves like an open circuit. When the completecircuit is prevented or blocked by inductive element 526, the highfrequency signals will be prevented on the lead LED+ and therefore willnot be reflected to the lead Line, thus preventing the undesirable EMIeffects. In some embodiments, the inductive element 526 is connectedbetween two of the fourth terminals respectively of the right end andleft end short circuit boards 253 at the two ends of the lamp tube. Insome embodiments, the inductive element 526 may comprise an inductorsuch as a choke inductor or a dual-inline-package inductor capable ofachieving a function of eliminating or reducing the above-mentioned EMIeffects of the lead (“Line”) disposed along the light strip 2 betweentwo of the first terminals (“L”) respectively at two ends of the lamptube. Therefore, this function can improve signal transmission (whichmay include transmissions through leads “L”, “LED+”, and “LED−”) of thepower supply in the LED tube lamp, and thus the qualities of the LEDtube lamp. Therefore, the LED tube lamp comprising the inductive element526 may effectively reduce EMI effects of the lead “L” or “Line”.Moreover, such an LED tube lamp may further comprise an installationdetection circuit or module, which is described below with reference toFIG. 15, for detecting whether or not the LED tube lamp is properlyinstalled in a lamp socket.

Referring to FIGS. 5 and 6, in another embodiment, the LED light stripand the power supply may be connected by utilizing a circuit boardassembly 25 configured with a power supply module 250 instead of solderbonding as described previously. The circuit board assembly 25 has along circuit sheet 251 and a short circuit board 253 that are adhered toeach other with the short circuit board 253 being adjacent to the sideedge of the long circuit sheet 251. The short circuit board 253 may beprovided with the power supply module 250 to form the power supply. Theshort circuit board 253 is stiffer or more rigid than the long circuitsheet 251 to be able to support the power supply module 250.

The long circuit sheet 251 may be the bendable circuit sheet of the LEDlight strip 2 including a wiring layer 2 a as shown in FIG. 2. Thewiring layer 2 a of the LED light strip 2 and the power supply module250 may be electrically connected in various manners depending on thedemand in practice. As shown in FIG. 5, the power supply module 250 andthe long circuit sheet 251 having the wiring layer 2 a on surface are onthe same side of the short circuit board 253 such that the power supplymodule 250 is directly connected to the long circuit sheet 251. As shownin FIG. 6, alternatively, the power supply module 250 and the longcircuit sheet 251 including the wiring layer 2 a on surface are onopposite sides of the short circuit board 253 such that the power supplymodule 250 is directly connected to the short circuit board 253 andindirectly connected to the wiring layer 2 a of the LED light strip 2 byway of the short circuit board 253.

The power supply module 250 and power supply 5 described above mayinclude various elements for providing power to the LED light strip 2.For example, they may include power converters or other circuit elementsand/or components for providing power to the LED light strip 2. Also, itshould be noted that the power supply 5 depicted and discussed in FIG. 1may also include a power supply module 250, though one is not labeled inFIG. 1. For example, the power supply module may be mounted on thecircuit board, as shown in FIG. 1, and may include power converters orother circuit elements and/or components for providing power to the LEDlight strip 2.

FIG. 4A is a perspective view of an exemplary bendable circuit sheet 200and a printed circuit board 420 of a power supply 400 soldered to eachother. FIG. 4B to FIG. 4D are diagrams illustrating an exemplarysoldering process of the bendable circuit sheet 200 and the printedcircuit board 420 of the power supply 400. In an embodiment, thestructure of the bendable circuit sheet 200 is similar to FIG. 3A. Thefreely extending portions are the portions of two opposite ends of thebendable circuit sheet 200 and are utilized for being connected to theprinted circuit board 420. Fixed portion is part of the light strip 200attached to the inner circumferential surface of the lamp tube. Thebendable circuit sheet 200 and the power supply 400 are electricallyconnected to each other by soldering. The bendable circuit sheet 200comprises a circuit layer 200 a and a circuit protection layer 200 cover a side of the circuit layer 200 a. Moreover, the bendable circuitsheet 200 comprises two opposite surfaces which are a first surface 2001and a second surface 2002. The first surface 2001 is the one on thecircuit layer 200 a and away from the circuit protection layer 200 c.The second surface 2002 is the other one on the circuit protection layer200 c and away from the circuit layer 200 a. Several LED light sources202 are disposed on the first surface 2001 and are electricallyconnected to circuits of the circuit layer 200 a. The circuit protectionlayer 200 c is made, for example, by polyimide (PI) having less thermalconductivity but being beneficial to protect the circuits. The firstsurface 2001 of the bendable circuit sheet 200 comprises soldering pads“b” (or referred as first soldering pads). Soldering material “g” can beplaced on the soldering pads “b”. In one embodiment, the bendablecircuit sheet 200 further comprises a notch “f”. The notch “f” isdisposed on an edge of the end of the bendable circuit sheet 200soldered to the printed circuit board 420 of the power supply 400. Insome embodiments instead of a notch, a hole near the edge of the end ofthe bendable circuit sheet 200 may be used, which may thus provideadditional contact material between the printed circuit board 420 andthe bendable circuit sheet 200, thereby providing a stronger connection.The printed circuit board 420 comprises a power circuit layer 420 a andsoldering pads “a”. Moreover, the printed circuit board 420 comprisestwo opposite surfaces which are a first surface (or a top surface) 421and a second surface (or a bottom surface) 422. The second surface 422is the one on the power circuit layer 420 a. The soldering pads “a” arerespectively disposed on the first surface 421 (those soldering pads “a”on the first surface 421 may be referred as second soldering pads) andthe second surface 422 (those soldering pads “a” on the second surface422 may be referred as third soldering pads). The soldering pads “a” onthe first surface 421 are corresponding to those on the second surface422. Soldering material “g” can be placed on the soldering pad “a”. Inone embodiment, considering the stability of soldering and theoptimization of automatic process, the bendable circuit sheet 200 isdisposed below the printed circuit board 420 (the direction is referredto FIG. 4B). For example, the first surface 2001 of the bendable circuitsheet 200 is connected to the second surface 422 of the printed circuitboard 420. Also, as shown, the soldering material “g” can contact,cover, and be soldered to a top surface of the bendable circuit sheet200 (e.g., first surface 2001), end side surfaces of soldering pads “a,”soldering pad “b,” and power circuit layer 420 a formed at an edge ofthe printed circuit board 420, and a top surface of soldering pad “a” atthe top surface 421 of the printed circuit board 420. In addition, thesoldering material “g” can contact side surfaces of soldering pads “a,”soldering pad “b,” and power circuit layer 420 a formed at a hole in theprinted circuit board 420 and/or at a hole or notch in bendable circuitsheet 200. The soldering material may therefore form a bump-shapedportion covering portions of the bendable circuit sheet 200 and theprinted circuit board 420, and a rod-shaped portion passing through theprinted circuit board 420 and through a hole or notch in the bendablecircuit sheet 200. The two portions (e.g., bump-shaped portion androd-shaped portion) may serve as a rivet, for maintaining a strongconnection between the bendable circuit sheet 200 and the printedcircuit board 420.

As shown in FIG. 4C and FIG. 4D, in an exemplary soldering process ofthe bendable circuit sheet 200 and the printed circuit board 420, thecircuit protection layer 200 c of the bendable circuit sheet 200 isplaced on a supporting table 42 (i.e., the second surface 2002 of thebendable circuit sheet 200 contacts the supporting table 42) in advanceof soldering. The soldering pads “a” on the second surface 422 of theprinted circuit board 420 contact the soldering pads “b” on the firstsurface 2001 of the bendable circuit sheet 200. And then a heating head41 presses on a portion of soldering material “g” where the bendablecircuit sheet 200 and the printed circuit board 420 are soldered to eachother. When soldering, the soldering pads “b” on the first surface 2001of the bendable circuit sheet 200 contact the soldering pads “a” on thesecond surface 422 of the printed circuit board 420, and the solderingpads “a” on the first surface 421 of the printed circuit board 420contact the soldering material “g,” which is pressed on by the heatinghead 41. Under this circumstance, the heat from the heating head 41 cantransmit through the soldering pads “a” on the first surface 421 of theprinted circuit board 420 and the soldering pads “a” on the secondsurface 422 of the printed circuit board 420 to the soldering pads “b”on the first surface 2001 of the bendable circuit sheet 200. Thetransmission of the heat between the heating heads 41 and the solderingpads “a” and “b” won't be affected by the circuit protection layer 200 cwhich has relatively less thermal conductivity, since the circuitprotection layer 200 c is not between the heating head 41 and thecircuit layer 200 a. Consequently, the efficiency and stabilityregarding the connections and soldering process of the soldering pads“a” and “b” of the printed circuit board 420 and the bendable circuitsheet 200 can be improved.

As shown in the exemplary embodiment of FIG. 4C, the printed circuitboard 420 and the bendable circuit sheet 200 are firmly connected toeach other by the soldering material “g”. Components between the virtualline M and the virtual line N of FIG. 4C from top to bottom are thesoldering pads “a” on the first surface 421 of printed circuit board420, the power circuit layer 420 a, the soldering pads “a” on the secondsurface 422 of printed circuit board 420, the soldering pads “b” on thefirst surface 2001 of bendable circuit sheet 200, the circuit layer 200a of the bendable circuit sheet 200, and the circuit protection layer200 c of the bendable circuit sheet 200. The connection of the printedcircuit board 420 and the bendable circuit sheet 200 are firm andstable. The soldering material “g” may extend higher than the solderingpads “a” on the first surface 421 of printed circuit board 420 and mayfill in other spaces, as described above.

In other embodiments, an additional circuit protection layer (e.g., PIlayer) can be disposed over the first surface 2001 of the circuit layer200 a. For example, the circuit layer 200 a may be sandwiched betweentwo circuit protection layers, and therefore the first surface 2001 ofthe circuit layer 200 a can be protected by the circuit protectionlayer. A part of the circuit layer 200 a (the part having the solderingpads “b”) is exposed for being connected to the soldering pads “a” ofthe printed circuit board 420. Other parts of the circuit layer 200 aare exposed by the additional circuit protection layer so they canconnect to LED light sources 202. Under these circumstances, a part ofthe bottom of each LED light source 202 contacts the circuit protectionlayer on the first surface 2001 of the circuit layer 200 a, and anotherpart of the bottom of the LED light source 202 contacts the circuitlayer 200 a.

According to the exemplary embodiments shown in FIG. 4A to FIG. 4D, theprinted circuit board 420 comprises through holes “h” passing throughthe soldering pads “a”. In an automatic soldering process, when theheating head 41 automatically presses the printed circuit board 420, thesoldering material “g” on the soldering pads “a” can be pushed into thethrough holes “h” by the heating head 41 accordingly. As a result, asoldered connection may be formed as shown in FIGS. 4C and 4D.

FIGS. 4A-4D illustrate embodiments of a soldering process between thelight strip 200 and the power supply module 400. According to FIGS.4A-4D, a structure of disposing the power supply module 400 on the topof the light strip 200 is provided. The soldering process can be appliedto the LED tube lamp with the single-end power supply structure or withthe dual-end power supply structure. Under the LED tube lamp withdual-end power supply structure, a route will be formed in the layout ofthe circuit layer of the light strip 200, so as to provide a currentpath for the commercial electricity flow through. When the LED tube lampis powered up, a current will flow through the light strip 200 from oneside to the other side via the current path and then will be input to arectifying circuit (also known as a rectifier).

FIG. 4E is a schematic structure of a freely extending portion of alight strip according to some exemplary embodiments. According to thesoldering structure of the light strip 200 and the power supply module400, an insulating sheet 210 having hollow holes k is disposed on thesoldering area of the light strip 200 as shown in FIG. 4E. Theinsulating sheet is formed of an electrically insulating material, whichmaterial may also have thermal insulating properties. The insulatingsheet 210 can be applied to the light strip 200 having two or moresoldering pads. The width of the insulating sheet 210 may besubstantially equal to the width of the light strip 200, and in oneembodiment, the length of the insulating sheet 210 is 1 to 50 times ofthe length of the soldering pads. In an exemplary embodiment, the lengthof the insulating sheet 210 is 10 times of the length of the solderingpads. The thickness of the insulating sheet may be, for example, 0.5 to5 times of the thickness of the light strip 200. In an exemplaryembodiment, the thickness of the insulating sheet is substantially equalto the thickness of the light strip. The shape of the hollow holescorrespond to or are the same as the shape of the soldering pads. Thearea of each hollow hole is slightly larger than the area of eachsoldering pad. In an exemplary embodiment, the area of each hollow holeranges from 101% to 200% of the area of each soldering pad.

The insulating sheet 210 is generally in a strip shape or an oval shape,and the design has advantages to overcome the following issues. First,the molten solder paste may diffuse to the periphery and cause a shortcircuit between the soldering pads when soldering. By disposing theinsulating sheet 210 on the light strip 200, the molten solder paste canbe surrounded by the hollow holes k, so that the solder paste does notdiffuse to the periphery and thus the risk of short circuit between thesoldering pads can be reduced. Second, since the ink of the solderingarea on the light strip 200 may be damaged when soldering, the leadscovered by the ink may be exposed and lead to the risk of short circuit.Disposing the insulating sheet 210 on the soldering area can protect theink and reduce the risk of short circuit so as to enhance thereliability of the soldering process. Third, since a high powerelectricity may apply to the lead (Line) of the light strip 200, thevoltage at the soldering area of the light strip 200 and the shortcircuit board may exceed 300V. In this situation, the ink covering thesurface of the light strip 200 can be broken down by the high voltageand lead to the risk of a short circuit. Disposing the insulating sheet210 on the light strip 200 may prevent the ink from being broken down soas to enhance the reliability of the soldering process.

The circuit connection between the light strip 200 and the power supplymodule 400 is described below in accordance with FIGS. 4E and 4F. Asshown in FIG. 4E, the light strip 200 has three soldering pads b10, b11and b12, and the soldering pads b10, b11 and b12 are arranged in twocolumns in the y direction. The circuit board (not shown) of the powersupply module 400 has three soldering pads disposed at the positioncorresponding to the soldering pads b10, b11 and b12. When performingthe soldering process by machines, there may be an offset, along the ydirection, between the soldering pads on the light strip 200 and thesoldering pads on the power supply module 400. As shown in FIG. 4F, theoffset may occur due to the soldering pads b11 and b12 and the solderingpads on the circuit board of the power supply module 400. According toFIG. 4F, the soldering pads of the power supply module 400 do notexactly coincide with the corresponding soldering pads b11 and b12,which means at least part of each soldering pad of the power supplymodule 400 faces an offset region of the light strip 200 withoutdirectly attaching to the corresponding soldering pad b11/b12. Due to aconductive layer, configured to conduct high power electricity, beingformed in the offset region, the ink coated on the offset region may bebroken down by the high voltage in certain situations, so that the shortcircuit occurs between the conductive layer of the offset region and thesoldering pads of the power supply module 400. In the presentembodiment, the above issue can be prevented since the insulating sheetis coated on the periphery region, including the offset region, of thesoldering pads b10, b11 and b12. Since the offset region is covered bythe insulating sheet, the ink of the offset region will not easily bebroken down by the high voltage. In some embodiments, the soldering padson either the light strip 200 or the power supply module 400 are coatedwith a solder paste. In another some embodiments, there are one orplural through holes formed on at least one of the soldering pads b10,b11 and b12, so as to improve the connection strength between the lightstrip 200 and the power supply module 400.

Referring to FIG. 3B again, the four soldering pads on the light strip,which are connected to the short circuit board 253 (e.g., pads “L”, “+”,“−” and “GND”), can be arranged in two columns. In some embodiments, thesoldering pad corresponding to the lead Line (or “L”) is disposed on aside close to an end portion of the light strip (similar to thearrangement of the soldering pad b10 illustrated in FIG. 4E), the otherthree soldering pads can be disposed in a column, on another side faraway from the end portion (similar to the arrangement of the solderingpads b11 and b12 illustrated in FIG. 4E). In some embodiments, two ofthe soldering pads are disposed on a side close to the end portion ofthe light strip and the other two of the soldering pads are disposed onanother side far away from the end portion, in which the lead Line isdisposed on the side close to the end portion. In some embodiments, thesoldering pads of the short circuit board 253 are soldered on the lightstrip as shown in FIGS. 4A to 4D, and insulating sheets having hollowholes are disposed on the soldering area of the light strip.

In some embodiments, the insulating sheet is made of one or acombination of Polyimide (PI), Polyethylene (PE), Polyvinylidenedifluoride (PVDF) and Polytetrafluoroethylene (PTFE). In someembodiments, the insulating sheet can be made of a PI film, which is thesame material as the light strip. The insulating sheet may be adhered tothe light strip by gluing or other connection means. In someembodiments, the length of the insulating sheet does not exceed thelength of the freely extending portion of the light strip. In someembodiments, the number of the soldering pads on the light strip can be2 or 4, and each soldering pad may further have one or plural throughholes for improving the connection strength between the light strip andthe circuit board of the power supply module.

FIG. 8A is a block diagram of a system including an LED tube lampincluding a power supply module according to certain embodiments.Referring to FIG. 8A, an alternating current (AC) power supply 508 isused to supply an AC supply signal, and may be an AC powerline with avoltage rating, for example, in 100-277V and a frequency rating, forexample, of 50 Hz or 60 Hz. A lamp driving circuit 505 receives the ACsupply signal from the AC power supply 508 and then converts it into anAC driving signal. The power supply module and power supply 508described above may include various elements for providing power to theLED light strip 2. For example, they may include power converters orother circuit elements for providing power to the LED light strip 2. Insome embodiments, the power supply 508 and the lamp driving circuit 505are outside of the LED tube lamp. For example, the lamp driving circuit505 may be part of a lamp socket or lamp holder into which the LED tubelamp is inserted. The lamp driving circuit 505 could be an electronicballast and may be used to convert the signal of commercial electricityinto high-frequency and high-voltage AC driving signal. The common typesof electronic ballast, such as instant-start electronic ballast,program-start electronic ballast, and rapid-start electronic ballast,can be applied to the LED tube lamp. In some embodiments, the voltage ofthe AC driving signal is bigger than 300V and in some embodiments400-700V with frequency being higher than 10 kHz and in some embodiments20-50 kHz. An LED tube lamp 500 receives the AC driving signal from thelamp driving circuit 505 and is thus driven to emit light. In thepresent embodiment, the LED tube lamp 500 is in a driving environment inwhich it is power-supplied at its one end cap having two conductive pins501 and 502 (which can be referred to the external connectionterminals), which are used to receive the AC driving signal. The twopins 501 and 502 may be electrically coupled to, either directly orindirectly, the lamp driving circuit 505.

In some embodiments, the lamp driving circuit 505 may be omitted and istherefore depicted by a dotted line. In certain embodiments, if the lampdriving circuit 505 is omitted, the AC power supply 508 is directlycoupled to the pins 501 and 502, which then receive the AC supply signalas the AC driving signal.

In an alternative to the application of the single-end power supplymentioned above, the LED tube lamp may be power-supplied at its both endcaps respectively having two conductive pins, which are coupled to thelamp driving circuit to concurrently receive the AC driving signal.Under the structure where the LED tube lamp having two end caps and eachend cap has two conductive pins, the LED tube lamp can be designed forreceiving the AC driving signal by one pin in each end cap, or by twopins in each end cap. An example of a circuit configuration of the powersupply module receiving the AC driving signal by one pin in each end capcan be seen in FIG. 8B (referred to as a “dual-end-single-pinconfiguration” hereinafter), which illustrates a block diagram of anexemplary power supply module for an LED tube lamp according to someexemplary embodiments. Referring to FIG. 8B, each end cap of the LEDtube lamp 500 could have only one conductive pin for receiving the ACdriving signal. For example, it is not required to have two conductivepins used in each end cap for the purpose of passing electricity throughthe both ends of the LED tube lamp. Compared to FIG. 8A, the conductivepins 501 and 502 in FIG. 8B are correspondingly configured at both endcaps of the LED tube lamp 500, and the AC power supply 508 and the lampdriving circuit 505 are the same as those mentioned above. The circuitconfiguration of the power supply module receiving the AC driving signalby two pins in each end cap can be referred to FIG. 8C (referred to“dual-end-dual-pin configuration” hereinafter), which illustrates ablock diagram of an exemplary power supply module for an LED tube lampaccording to some exemplary embodiments. Compared to FIG. 8A and FIG.8B, the present embodiment further includes pins 503 and 504. One endcap of the lamp tube has the pins 501 and 502, and the other end cap ofthe lamp tube has the pins 503 and 504. The pins 501 to 504 areconnected to the lamp driving circuit 505 to collectively receive the ACdriving signal, and thus the LED light sources (not shown) in the LEDtube lamp 500 are driven to emit light.

Under the dual-end-dual-pin configuration, no matter whether the ACdriving signal is provided to two pins on one of the end caps, one pinon each end cap, or two pins on each end cap, the AC driving signal canbe used for the operating power of the LED tube lamp by rearranging thecircuit configuration of the power supply module. When the AC drivingsignal is provided to one pin on each end cap (i.e., differentpolarities of the AC driving signal are respectively provided to the twoend caps), in an exemplary embodiment, another one pin on each end capis set to a floating state. For example, the pins 502 and 503 can be setto the floating state, so that the tube lamp receives the AC drivingsignal via the pins 501 and 504. The power supply module performsrectification and filtering to the AC driving signal received from thepins 501 and 504. In another exemplary embodiment, both pins on the sameend cap are connected to each other, for example, the pin 501 isconnected to the pin 502 on the left end cap, and the pin 503 isconnected to the pin 504 on the right end cap. Therefore, the pins 501and 502 can be used for receiving the positive or negative AC drivingsignal, and the pins 503 and 504 can be used for receiving the ACdriving signal having opposite polarity with the signal received by thepins 501 and 502. Thus, the power supply module within the tube lamp mayperform the rectification and filtering to the received signal. When theAC driving signal is provided to two pins on each end cap, the pins onthe same side may receive the AC driving signal having differentpolarity. For example, the pins 501 and 502 may receive the AC drivingsignal having opposite polarity, the pins 503 and 504 may receive the ACdriving signal having opposite polarity, and the power supply modulewithin the tube lamp may perform the rectification and filtering to thereceived signal.

FIG. 8D is a block diagram of an LED lamp according to one embodiment.Referring to FIG. 8D, the power supply module of the LED lamp includes arectifying circuit 510, a filtering circuit 520, and may further includesome parts of an LED lighting module 530. The rectifying circuit 510 iscoupled to two pins 501 and 502 to receive and then rectify an externaldriving signal, so as to output a rectified signal at two rectifyingoutput terminals 511 and 512. In some embodiments, the external drivingsignal may be the AC driving signal or the AC supply signal describedwith reference to FIGS. 8A and 8B. In some embodiments, the externaldriving signal may be a direct current (DC) signal without altering theLED tube lamp. The filtering circuit 520 is coupled to the rectifyingcircuit for filtering the rectified signal to produce a filtered signal.For instance, the filtering circuit 520 is coupled to the rectifyingcircuit output terminals 511 and 512 to receive and then filter therectified signal, so as to output a filtered signal at two filteringoutput terminals 521 and 522. The LED lighting module 530 is coupled tothe filtering circuit 520 to receive the filtered signal for emittinglight. For instance, the LED lighting module 530 may include a circuitcoupled to the filtering output terminals 521 and 522 to receive thefiltered signal and thereby to drive an LED unit (not shown) in the LEDlighting module 530 to emit light. Details of these operations aredescribed below in accordance with certain embodiments.

FIG. 8E is a block diagram of an exemplary LED lamp according to someexemplary embodiments. Referring to FIG. 8E, the power supply module ofthe LED lamp includes a first rectifying circuit 510, a filteringcircuit 520, an LED lighting module 530 and a second rectifying circuit540, which can be utilized in the single-end power supply configurationillustrated in FIG. 8A or the dual-end power supply configurationillustrated in FIGS. 8B and 8C. The first rectifying circuit 510 iscoupled to the pins 501 and 502 to receive and then rectify an externaldriving signal transmitted by the pins 501 and 502; the secondrectifying circuit 540 is coupled to the pins 503 and 504 to receive andthen rectify an external driving signal transmitted by pins 503 and 504.The first rectifying circuit 510 and the second rectifying circuit 540of the power supply module collectively output a rectified signal at tworectifying circuit output terminals 511 and 512. The filtering circuit520 is coupled to the rectifying circuit output terminals 511 and 512 toreceive and then filter the rectified signal, so as to output a filteredsignal at two filtering output terminals. The LED lighting module 530 iscoupled to the filtering output terminals to receive the filteredsignal, so as to drive the LED light source (not shown) for emittinglight.

FIG. 8F is a block diagram of an exemplary LED lamp according to someexemplary embodiments. Referring to FIG. 8F, the power supply module ofLED tube lamp includes a rectifying circuit 510′, a filtering circuit520 and part of an LED light module 530, which can also be utilized inthe single-end power supply configuration illustrated in FIG. 8A or thedual-end power supply configuration illustrated in FIGS. 8B and 8C. Thedifference between the embodiments illustrated in FIG. 8F and FIG. 8E isthat the rectifying circuit 510′ has three input terminals to be coupledto the pins 501 to 503, respectively. The rectifying circuit 510′rectifies the signals received from the pins 501 to 503, in which thepin 504 can be set to the floating state or connected to the pin 503.Therefore, the second rectifying circuit 540 can be omitted in thepresent embodiment. The rest of circuitry operates substantially thesame as the embodiment illustrated in FIG. 8E, so that the detaileddescription is not repeated herein.

Although there are two rectifying output terminals 511 and 512 and twofiltering output terminals 521 and 522 in the embodiments of theseFigs., in practice the number of ports or terminals for coupling betweenthe rectifying circuit 510, the filtering circuit 520, and the LEDlighting module 530 may be one or more depending on the needs of signaltransmission between the circuits or devices.

In addition, the power supply module of the LED lamp described in FIG.8D, and embodiments of a power supply module of an LED lamp describedbelow, may each be used in the LED tube lamp 500 in FIGS. 8A and 8B, andmay instead be used in any other type of LED lighting structure havingtwo conductive pins used to conduct power, such as LED light bulbs,personal area lights (PAL), plug-in LED lamps with different types ofbases (such as types of PL-S, PL-D, PL-T, PL-L, etc.), etc. Further, theimplementation for LED light bulbs may provide better effects onprotecting from electric shock as combining this invention and thestructures disclosed in EU patent application WO2016045631.

When the LED tube lamp 500 is applied to the dual-end power structurewith at least one pin, retrofit can be performed to a lamp socketincluding a lamp driving circuit or a ballast 505, so as to bypass theballast 505 and provide the AC power supply (e.g., commercialelectricity) as the power source of the LED tube lamp. FIG. 8G is ablock diagram of a connection configuration between an LED lamp and anexternal power source according to some exemplary embodiments. Comparedto FIG. 8A, the embodiment illustrated in FIG. 8G further provides aballast bypass module 506 disposed between the AC power supply 508 andthe ballast 505. The rest of the circuit modules perform the same orsimilar function with the embodiment illustrated in FIG. 8B. The ballastbypass module 506, also described as a ballast bypass circuit, receivesthe power provided by the AC power supply 508, and is connected to thepins 501 and 502 of the LED tube lamp 500 illustrated in FIG. 8G (inwhich the ballast bypass module 506 is also connected to the ballast 505for performing specific control). The ballast bypass module 506 isconfigured to bypass the electricity received from the AC power supply508 and then output to the pins 501 and 502 for providing power to theLED tube lamp 500. In some exemplary embodiments, the ballast bypassmodule 506 includes a switch circuit configured to bypass the ballast505, in which the switch circuit includes, for example, a component or adevice such as an electrical switch or an electronic switch. One skilledin the art of fluorescent lighting may understand or design a feasiblestructure or circuit that constitutes the ballast bypass module 506.Furthermore, the ballast bypass module 506 can be disposed in atraditional fluorescent lamp socket having the ballast 505, or in thepower supply module 5 or 250 of the LED tube lamp 500. Furthermore, ifthe bypass function of the ballast bypass module 506 is suspended, theequivalent connection configuration between the LED tube lamp and theexternal power source is similar to the configuration illustrated inFIG. 8A to FIG. 8C, in which the ballast 505 is still coupled to thepins 501 and 502, so that the LED tube lamp 500 still can be powered(i.e., receive AC power supply 508) through the ballast 505. Thismodification (adding the ballast bypass module 506) allows the LED tubelamp 500 to compatibly receive power, provided by the AC power supply508 (but not provided by the ballast 505), through the dual-end pinconfiguration even though the LED tube lamp 500 is installed on a lampsocket having the ballast 505.

FIG. 9A is a schematic diagram of a rectifying circuit according to anembodiment. Referring to FIG. 9A, a rectifying circuit 610, i.e. abridge rectifier, includes four rectifying diodes 611, 612, 613, and614, configured to full-wave rectify a received signal. The diode 611has an anode connected to the output terminal 512, and a cathodeconnected to the pin 502. The diode 612 has an anode connected to theoutput terminal 512, and a cathode connected to the pin 501. The diode613 has an anode connected to the pin 502, and a cathode connected tothe output terminal 511. The diode 614 has an anode connected to the pin501, and a cathode connected to the output terminal 511.

When the pins 501 and 502 receive an AC signal, the rectifying circuit610 operates as follows. During the connected AC signal's positive halfcycle, the AC signal is input through the pin 501, the diode 614, andthe output terminal 511 in sequence, and later output through the outputterminal 512, the diode 611, and the pin 502 in sequence. During theconnected AC signal's negative half cycle, the AC signal is inputthrough the pin 502, the diode 613, and the output terminal 511 insequence, and later output through the output terminal 512, the diode612, and the pin 501 in sequence. Therefore, during the connected ACsignal's full cycle, the positive pole of the rectified signal producedby the rectifying circuit 610 keeps at the output terminal 511, and thenegative pole of the rectified signal remains at the output terminal512. Accordingly, the rectified signal produced or output by therectifying circuit 610 is a full-wave rectified signal.

When the pins 501 and 502 are coupled to a DC power supply to receive aDC signal, the rectifying circuit 610 operates as follows. When the pin501 is coupled to the positive end of the DC power supply and the pin502 to the negative end of the DC power supply, the DC signal is inputthrough the pin 501, the diode 614, and the output terminal 511 insequence, and later output through the output terminal 512, the diode611, and the pin 502 in sequence. When the pin 501 is coupled to thenegative end of the DC power supply and the pin 502 to the positive endof the DC power supply, the DC signal is input through the pin 502, thediode 613, and the output terminal 511 in sequence, and later outputthrough the output terminal 512, the diode 612, and the pin 501 insequence. Therefore, no matter what the electrical polarity of the DCsignal is between the pins 501 and 502, the positive pole of therectified signal produced by the rectifying circuit 610 keeps at theoutput terminal 511, and the negative pole of the rectified signalremains at the output terminal 512.

Therefore, the rectifying circuit 610 in this embodiment can output orproduce a proper rectified signal regardless of whether the receivedinput signal is an AC or DC signal.

FIG. 9B is a schematic diagram of a rectifying circuit according to anembodiment. Referring to FIG. 9B, a rectifying circuit 710 includes tworectifying diodes 711 and 712, configured to half-wave rectify areceived signal. The rectifying diode 711 has an anode connected to thepin 502, and a cathode connected to the rectifying output terminal 511.The rectifying diode 712 has an anode connected to the rectifying outputterminal 511, and a cathode connected to the pin 501. The rectifyingoutput terminal 512 can be omitted or connect to ground according to thepractical application. Detailed operations of the rectifying circuit 710are described below.

During the connected AC signal's positive half cycle, the signal levelof the AC signal input through the pin 501 is greater than the signallevel of the AC signal input through the pin 502. At that time, both therectifying diodes 711 and 712 are cut off since being reverse biased,and thus the rectifying circuit 710 stops outputting the rectifiedsignal. During the connected AC signal's negative half cycle, the signallevel of the AC signal input through the pin 501 is less than the signallevel of the AC signal input through the pin 502. At that time, both therectifying diodes 711 and 712 are conducting since they are forwardbiased, and thus the AC signal is input through the pin 502, therectifying diode 711, and the rectifying output terminal 511 insequence, and later output through the rectifying output terminal 512 oranother circuit or ground of the LED tube lamp. Accordingly, therectified signal produced or output by the rectifying circuit 710 is ahalf-wave rectified signal.

It should be noted that, when the pins 501 and 502 shown in FIG. 9A andFIG. 9B are respectively changed to the pins 503 and 504, the rectifyingcircuit 610 and 710 can be considered as the rectifying circuit 540illustrated in FIG. 8E. More specifically, in an exemplary embodiment,when the full-wave rectifying circuit 610 shown in FIG. 9A is applied tothe dual-end tube lamp shown in FIG. 8E, the configuration of therectifying circuits 510 and 540 is shown in FIG. 9C. FIG. 9C is aschematic diagram of a rectifying circuit according to an embodiment.

Referring to FIG. 9C, the rectifying circuit 640 has the sameconfiguration as the rectifying circuit 610, which is the bridgerectifying circuit. The rectifying circuit 610 includes four rectifyingdiodes 611 to 614, which has the same configuration as the embodimentillustrated in FIG. 9A. The rectifying circuit 640 includes fourrectifying diodes 641 to 644 and is configured to perform full-waverectification on the received signal. The rectifying diode 641 has ananode coupled to the rectifying output terminal 512, and a cathodecoupled to the pin 504. The rectifying diode 642 has an anode coupled tothe rectifying output terminal 512, and a cathode couple to the pin 503.The rectifying diode 643 has an anode coupled to the pin 502, and acathode coupled to the rectifying output terminal 511. The rectifyingdiode 644 has an anode coupled to the pin 503, and a cathode coupled tothe rectifying output terminal 511.

In the present embodiment, the rectifying circuits 610 and 640 areconfigured to correspond to each other, in which the difference betweenthe rectifying circuits 610 and 640 is that the input terminal of therectifying circuit 610 (which can be used as the rectifying circuit 510shown in FIG. 8E) is coupled to the pins 501 and 502, buy the inputterminal of the rectifying circuit 640 (which can be used as therectifying circuit 540 shown in FIG. 8E) is coupled to the pins 503 and504. Therefore, the present embodiment applies a structure including twofull-wave rectifying circuits for implementing the dual-end-dual-pincircuit configuration.

In some embodiments, in the rectifying circuit illustrated in theexample of FIG. 9C, although the circuit configuration is disposed asthe dual-end-dual-pin configuration, the external driving signal is notlimited to be provided through both pins on each end cap. Under theconfiguration shown in FIG. 9C, no matter whether the AC signal isprovided through both pins on single end cap or through signal pin oneach end cap, the rectifying circuit shown in FIG. 9C may correctlyrectify the received signal and generate the rectified signal forlighting the LED tube lamp. Detailed operations are described below.

When the AC signal is provided through both pins on single end cap, theAC signal can be applied to the pins 501 and 502, or to the pins 503 and504. When the AC signal is applied to the pins 501 and 502, therectifying circuit 610 performs full-wave rectification on the AC signalbased on the operation illustrated in the embodiment of FIG. 9A, and therectifying circuit 640 does not operate. On the contrary, when theexternal driving signal is applied to the pins 503 and 504, therectifying circuit 640 performs full-wave rectification on the AC signalbased on the operation illustrated in the embodiment of FIG. 9A, and therectifying circuit 610 does not operate.

When the AC signal is provided through a single pin on each end cap, theAC signal can be applied to the pins 501 and 504, or to the pins 502 and503. For example, the dual pins on each end cap can be arranged based onstandard socket configuration so that the AC signal will be applied toeither pins 501 and 504 or pins 502 and 503, but not pins 501 and 503 orpins 502 and 504 (e.g., based on the physical positioning of the pins oneach end cap).

When the AC signal is applied to the pins 501 and 504, during the ACsignal's positive half cycle (e.g., the voltage at pin 501 is higherthan the voltage at pin 504), the AC signal is input through the pin501, the diode 614, and the output terminal 511 in sequence, and lateroutput through the output terminal 512, the diode 641, and the pin 504in sequence. In this manner, output terminal 511 remains at a highervoltage than output terminal 512. During the AC signal's negative halfcycle (e.g., the voltage at pin 504 is higher than the voltage at pin501), the AC signal is input through the pin 504, the diode 643, and theoutput terminal 511 in sequence, and later output through the outputterminal 512, the diode 612, and the pin 501 in sequence. In thismanner, output terminal 511 still remains at a higher voltage thanoutput terminal 512. Therefore, during the AC signal's full cycle, thepositive pole of the rectified signal remains at the output terminal511, and the negative pole of the rectified signal remains at the outputterminal 512. Accordingly, the diodes 612 and 614 of the rectifyingcircuit 610 and the diodes 641 and 643 of the rectifying circuit 640 areconfigured to perform the full-wave rectification on the AC signal andthus the rectified signal produced or output by the diodes 612, 614,641, and 643 is a full-wave rectified signal.

On the other hand, when the AC signal is applied to the pins 502 and503, during the AC signal's positive half cycle (e.g., the voltage atpin 502 is higher than the voltage at pin 503), the AC signal is inputthrough the pin 502, the diode 613, and the output terminal 511 insequence, and later output through the output terminal 512, the diode642, and the pin 503. During the AC signal's negative half cycle (e.g.,the voltage at pin 503 is higher than the voltage at pin 502), the ACsignal is input through the pin 503, the diode 644, and the outputterminal 511 in sequence, and later output through the output terminal512, the diode 611, and the pin 502 in sequence. Therefore, during theAC signal's full cycle, the positive pole of the rectified signalremains at the output terminal 511, and the negative pole of therectified signal remains at the output terminal 512. Accordingly, thediodes 611 and 613 of the rectifying circuit 610 and the diodes 642 and644 of the rectifying circuit 640 are configured to perform thefull-wave rectification on the AC signal and thus the rectified signalproduced or output by the diodes 611, 613, 642, and 644 is a full-waverectified signal.

When the AC signal is provided through two pins on each end cap, theoperation in each of the rectifying circuits 610 and 640 can be referredto the embodiment illustrated in FIG. 9A, and it will not be repeatedherein. The rectified signal produced by the rectifying circuits 610 and640 is output to the rear-end circuit after superposing on the outputterminals 511 and 512.

In an exemplary embodiment, the rectifying circuit 510′ illustrated inFIG. 8F can be implemented by the configuration illustrated in FIG. 9D.FIG. 9D is a schematic diagram of a rectifying circuit according to anembodiment. Referring to FIG. 9D, the rectifying circuit 910 includesdiodes 911 to 914, which are configured as the embodiment illustrated inFIG. 9A. In the present embodiment, the rectifying circuit 910 furtherincludes rectifying diodes 915 and 916. The diode 915 has an anodecoupled to the rectifying output terminal 512, and a cathode coupled tothe pin 503. The diode 916 has an anode coupled to the pin 503, and acathode coupled to the rectifying output terminal 511. The pin 504 isset to the float state in the present embodiment.

Specifically, the rectifying circuit 910 can be regarded as a rectifyingcircuit including three sets of bridge arms, in which each of the bridgearms provides an input signal receiving terminal. For example, thediodes 911 and 913 constitute a first bridge arm for receiving thesignal on the pin 502; the diodes 912 and 914 constitute a second bridgearm for receiving the signal on the pin 501; and the diodes 915 and 916constitute a third bridge arm for receiving the signal on the pin 503.According to the rectifying circuit 910 illustrated in FIG. 9D, thefull-wave rectification can be performed as long as different polarityAC signal is respectively received by two of the bridge arms.Accordingly, under the configuration illustrated in FIG. 9D, no matterwhat kind of power supply configuration, such as the AC signal beingprovided to both pins on single end cap, a single pin on each end cap,or both pins on each end cap, the rectifying circuit 910 is compatiblefor producing the rectified signal, correctly. Detailed operations ofthe present embodiment are described below.

When the AC signal is provided through both pins on single end cap, theAC signal can be applied to the pins 501 and 502. The diodes 911 to 914perform full-wave rectification on the AC signal based on the operationillustrated in the embodiment of FIG. 9A, and the diodes 915 and 916 donot operate.

When the AC signal is provided through single pin on each end cap, theAC signal can be applied to the pins 501 and 503, or to the pins 502 and503. When the AC signal is applied to the pins 501 and 503, during theAC signal's positive half cycle (e.g., when the signal on pin 501 has alarger voltage than the signal on pin 503), the AC signal is inputthrough the pin 501, the diode 914, and the output terminal 511 insequence, and later output through the output terminal 512, the diode915, and the pin 503 in sequence. During the AC signal's negative halfcycle (e.g., when the signal on pin 503 has a larger voltage than thesignal on pin 501), the AC signal is input through the pin 503, thediode 916, and the output terminal 511 in sequence, and later outputthrough the output terminal 512, the diode 912, and the pin 501 insequence. Therefore, during the AC signal's full cycle, the positivepole of the rectified signal remains at the output terminal 511, and thenegative pole of the rectified signal remains at the output terminal512. Accordingly, the diodes 912, 914, 915, and 916 of the rectifyingcircuit 910 are configured to perform the full-wave rectification on theAC signal and thus the rectified signal produced or output by the diodes912, 914, 915, and 916 is a full-wave rectified signal.

On the other hand, when the AC signal is applied to the pins 502 and503, during the AC signal's positive half cycle (e.g., when the signalon pin 502 has a larger voltage than the signal on pin 503), the ACsignal is input through the pin 502, the diode 913, and the outputterminal 511 in sequence, and later output through the output terminal512, the diode 915, and the pin 503. During the AC signal's negativehalf cycle (e.g., when the signal on pin 503 has a larger voltage thanthe signal on pin 502), the AC signal is input through the pin 503, thediode 916, and the output terminal 511 in sequence, and later outputthrough the output terminal 512, the diode 911, and the pin 502 insequence. Therefore, during the AC signal's full cycle, the positivepole of the rectified signal remains at the output terminal 511, and thenegative pole of the rectified signal remains at the output terminal512. Accordingly, the diodes 911, 913, 915, and 916 of the rectifyingcircuit 910 are configured to perform the full-wave rectification on theAC signal and thus the rectified signal produced or output by the diodes911, 913, 915, and 916 is a full-wave rectified signal.

When the AC signal is provided through two pins on each end cap, theoperation of the diodes 911 to 914 can be referred to the embodimentillustrated in FIG. 9A, and it will not be repeated herein. Also, if thesignal polarity of the pin 503 is the same as the pin 501, the operationof the diodes 915 and 916 is similar to that of the diodes 912 and 914(i.e., the first bridge arm). On the other hand, if the signal polarityof the pin 503 is the same as that of the pin 502, the operation of thediodes 915 and 916 is similar with the diodes 912 and 914 (i.e., thesecond bridge arm).

FIG. 9E is a schematic diagram of a rectifying circuit according to anembodiment. Referring to FIG. 9E, the difference between the embodimentsof FIG. 9E and FIG. 9D is that the rectifying circuit shown in FIG. 9Efurther includes a terminal adapter circuit 941. The terminal adaptercircuit 941 includes fuses 947 and 948. One end of the fuse 947 iscoupled to the pin 501, and the other end of the fuse 947 is coupled tothe connection node of the diodes 912 and 914 (i.e., the input terminalof the first bridge arm). One end of the fuse 948 is coupled to the pin502, and the other end of the fuse 948 is coupled to the connection nodeof the diodes 911 and 913 (i.e., the input terminal of the second bridgearm). Accordingly, when the current flowing through any one of the pins501 and 502 is higher than the rated current of the fuses 947 and 948,the fuse 947/948 will be fused (e.g., broken) in response to the currentso as to form an open circuit between the pin 501/502 and the rectifyingcircuit 910, thereby achieving the function of over current protection.In the case of only one of the fuses 947 and 948 being fused (e.g., theover current situation just happens in a brief period and then iseliminated), if the AC driving signal is provided through both pins oneach end cap, the rectifying circuit still works, after the over currentsituation is eliminated, since the AC driving signal can be providedthrough single pin on each end cap.

FIG. 9F is a schematic diagram of a rectifying circuit according to anembodiment. Referring to FIG. 9F, the difference between the embodimentsof FIG. 9F and FIG. 9D is that the pins are connected to each otherthrough a thin wire 917. Compared to the embodiments illustrated in FIG.9D or FIG. 9E, when the AC signal is applied to the dual-end-single-pinconfiguration, no matter the AC signal is applied to the pin 503 or thepin 504, the rectifying circuit of the present embodiment can benormally operated. Furthermore, when the pins 503 and 504 are installedon the wrong lamp socket which provides the AC signal to the single endcap, the thin wire 917 can be reliably fused. Therefore, when the lampis installed on the correct lamp socket, the tube lamp utilizing therectifying illustrated in FIG. 9F may keep working, normally.

According to the embodiments mentioned above, the rectifying circuitsillustrated in FIG. 9C to 9F are compatible for receiving the AC signalthrough both pins on single end cap, through single pin on each end cap,and through both pins on each end cap, such that the compatibility ofthe LED tube lamp's application is improved. In this manner, an LED tubelamp can include a rectifying circuit that is arranged to rectify an ACsignal in all of the following situations: when the LED tube lamp isconnected (e.g., coupled to a socket) to receive the AC signal throughboth of two pins on a single end cap; when the LED tube lamp isconnected (e.g., coupled to a socket) to receive the AC signal throughboth of two pins on each end cap; and when the LED tube lamp isconnected (e.g., coupled to a socket) to receive the AC signal through asingle pin on each end cap. In addition, based on the aspect of theactual circuit layout scenario, the embodiments illustrated in FIG. 9Dto 9F require only three power pads for connecting the correspondingpins, so that the process yield can be significant enhanced since themanufacture process of the three pads configuration is easier than thefour power pads configuration.

In some embodiments, one or plural varistors (also known as voltagedependent resistor (VDR)) is disposed on the input side or the outputside of the rectifying circuit. The varistor is configured to protectagainst excessive transient voltages by shunting the current created bythe excessive voltage. According to some embodiments of disposing thevaristor on the input side of the rectifying circuit, the varistor iselectrically connected between the pins 501 and 502. According to someembodiments of disposing the varistor on the output side of therectifying circuit, the varistor is electrically connected between therectifying output terminals 511 and 512. In some embodiments, thevaristor can be designed for smaller size by disposing the varistor onthe output side of the rectifying circuit. In some embodiments, the sizeof the varistor disposed on the output side of the rectifying circuitcan be half of the varistor disposed on the input side of the rectifyingcircuit.

FIG. 10A is a block diagram of the filtering circuit according to anembodiment. A rectifying circuit 510 is shown in FIG. 10A forillustrating its connection with other components, without intending afiltering circuit 520 to include the rectifying circuit 510. Referringto FIG. 10A, the filtering circuit 520 includes a filtering unit 523coupled to two rectifying output terminals 511 and 512 to receive and tofilter out ripples of a rectified signal from the rectifying circuit510. Accordingly, the waveform of a filtered signal is smoother thanthat of the rectified signal. The filtering circuit 520 may furtherinclude another filtering unit 524 coupled between a rectifying circuitand a pin correspondingly, for example, between the rectifying circuit510 and the pin 501, the rectifying circuit 510 and the pin 502, therectifying circuit 540 and the pin 503, and/or the rectifying circuit540 and the pin 504. The filtering unit 524 is used to filter a specificfrequency, for example, to filter out a specific frequency of anexternal driving signal. In this embodiment, the filtering unit 524 iscoupled between the rectifying circuit 510 and the pin 501. Thefiltering circuit 520 may further include another filtering unit 525coupled between one of the pins 501 and 502 and one of the diodes of therectifying circuit 510, or between one of the pins 503 and 504 and oneof the diodes of the rectifying circuit 540 to reduce or filter outelectromagnetic interference (EMI). In this embodiment, the filteringunit 525 is coupled between the pin 501 and one of diodes (not shown inFIG. 10A) of the rectifying circuit 510. Since the filtering units 524and 525 may be present or omitted depending on actual circumstances oftheir uses, they are depicted by a dotted line in FIG. 10A.

FIG. 10B is a schematic diagram of the filtering unit according to anembodiment. Referring to FIG. 10B, a filtering unit 623 includes acapacitor 625 having an end coupled to the output terminal 511 and afiltering output terminal 521 and the other end thereof coupled to theoutput terminal 512 and a filtering output terminal 522, and isconfigured to low-pass filter a rectified signal from the outputterminals 511 and 512, so as to filter out high-frequency components ofthe rectified signal and thereby output a filtered signal at thefiltering output terminals 521 and 522.

FIG. 10C is a schematic diagram of the filtering unit according to anembodiment. Referring to FIG. 10C, a filtering unit 723 includes a pifilter circuit including a capacitor 725, an inductor 726, and acapacitor 727. As is well known, a pi filter circuit looks like thesymbol π in its shape or structure. The capacitor 725 has an endconnected to the output terminal 511 and coupled to the filtering outputterminal 521 through the inductor 726, and has another end connected tothe output terminal 512 and the filtering output terminal 522. Theinductor 726 is coupled between output terminal 511 and the filteringoutput terminal 521. The capacitor 727 has an end connected to thefiltering output terminal 521 and coupled to the output terminal 511through the inductor 726, and has another end connected to the outputterminal 512 and the filtering output terminal 522.

As seen between the output terminals 511 and 512 and the filteringoutput terminals 521 and 522, the filtering unit 723 compared to thefiltering unit 623 in FIG. 10B additionally has an inductor 726 and acapacitor 727, which perform the function of low-pass filtering like thecapacitor 725 does. Therefore, the filtering unit 723 in this embodimentcompared to the filtering unit 623 in FIG. 10B has a better ability tofilter out high-frequency components to output a filtered signal with asmoother waveform.

The inductance values of the inductor 726 in the embodiments mentionedabove are chosen in the range of, for example in some embodiments, about10 nH to 10 mH. And the capacitance values of the capacitors 625, 725,and 727 in the embodiments stated above are chosen in the range of, forexample in some embodiments, about 100 pF to 1 uF.

FIG. 11A is a schematic diagram of an LED module according to anembodiment. Referring to FIG. 11A, an LED module 630 has an anodeconnected to a filtering output terminal 521, a cathode connected to afiltering output terminal 522, and includes at least one LED unit 632,such as the light source mentioned above. When two or more LED units areincluded, they are connected in parallel. The anode of each LED unit 632is connected to the anode of LED module 630 to couple with the filteringoutput terminal 521, and the cathode of each LED unit 632 is connectedto the cathode of LED module 630 to couple to the filtering outputterminal 522. Each LED unit 632 includes at least one LED 631. Whenmultiple LEDs 631 are included in an LED unit 632, they are connected inseries with the anode of the first LED 631 connected to the anode ofthis LED unit 632 (the anode of the first LED 631 and the anode of theLED unit 632 may be the same terminal) and the cathode of the first LED631 connected to the next or second LED 631. And the anode of the lastLED 631 in this LED unit 632 is connected to the cathode of a previousLED 631 and the cathode of the last LED 631 connected to the cathode ofthis LED unit 632 (the cathode of the last LED 631 and the cathode ofthe LED unit 632 may be the same terminal).

In some embodiments, the LED module 630 may produce a current detectionsignal S531 reflecting the magnitude of current through the LED module630 and being used for controlling or detecting the LED module 630.

FIG. 11B is a schematic diagram of an LED module according to anexemplary embodiment. Referring to FIG. 11B, an LED module 630 has ananode connected to a filtering output terminal 521, a cathode connectedto a filtering output terminal 522, and includes at least two LED units732 with the anode of each LED unit 732 connected to the anode of LEDmodule 630 and the cathode of each LED unit 732 connected to the cathodeof LED module 630 (the anode of each LED unit 732 and the anode of theLED module 630 may be the same terminal, and the cathode of each LEDunit 732 and the cathode of the LED module 630 may be the sameterminal). Each LED unit 732 includes at least two LEDs 731 connected inthe same way as those described in FIG. 11A. For example, the anode ofthe first LED 731 in an LED unit 732 is connected to the anode of thisLED unit 732, the cathode of the first LED 731 is connected to the anodeof the next or second LED 731, and the cathode of the last LED 731 isconnected to the cathode of this LED unit 732. Further, LED units 732 inan LED module 630 are connected to each other in this embodiment. All ofthe n-th LEDs 731 in the related LED units 732 thereof are connected bytheir anodes and cathodes, such as those shown in FIG. 11B but not limitto, where n is a positive integer. In this way, the LEDs in the LEDmodule 630 of this embodiment are connected in the form of a mesh.

In some embodiments, the LED lighting module 530 in the aboveembodiments includes the LED module 630, but doesn't include a drivingcircuit for the LED module 630.

Also, the LED module 630 in this embodiment may produce a currentdetection signal S531 reflecting the magnitude of current through theLED module 630 and being used for controlling or detecting the LEDmodule 630.

In some embodiments, the number of LEDs 731 included by an LED unit 732is in the range of 15-25, and may be in some embodiments in the range of18-22.

FIG. 11C is a plan view of a circuit layout of the LED module accordingto an embodiment. Referring to FIG. 11C, in this embodiment, multipleLEDs 831 are connected in the same way as described in FIG. 11B, andthree LED units are assumed in the LED module 630 and described asfollows for illustration. A positive conductive line 834 and a negativeconductive line 835 are to receive a driving signal for supplying powerto the LEDs 831. For example, the positive conductive line 834 may becoupled to the filtering output terminal 521 of the filtering circuit520 described above, and the negative conductive line 835 coupled to thefiltering output terminal 522 of the filtering circuit 520 to receive afiltered signal. For the convenience of illustration, all three of then-th LEDs 831 in the three related LED units thereof are grouped as anLED set 833 in FIG. 11C.

The positive conductive line 834 connects the three first LEDs 831 ofthe leftmost three related LED units thereof, for example, connects theanodes on the left sides of the three first LEDs 831 as shown in theleftmost LED set 833 of FIG. 11C. The negative conductive line 835connects the three last LEDs 831 of the rightmost three correspondingLED units thereof, for example, connects the cathodes on the right sidesof the three last LEDs 831 as shown in the rightmost LED set 833 of FIG.11C. The cathodes of the three first LEDs 831, the anodes of the threelast LEDs 831, and the anodes and cathodes of all the remaining LEDs 831are connected by conductive lines or parts 839.

For example, the anodes of the three LEDs 831 in the leftmost LED set833 may be connected together by the positive conductive line 834, andtheir cathodes may be connected together by a leftmost conductive part839. The anodes of the three LEDs 831 in the second, next-leftmost LEDset 833 are also connected together by the leftmost conductive part 839,whereas their cathodes are connected together by a second, next-leftmostconductive part 839. Since the cathodes of the three LEDs 831 in theleftmost LED set 833 and the anodes of the three LEDs 831 in the second,next-leftmost LED set 833 are connected together by the same leftmostconductive part 839, the cathode of the first LED 831 in each of thethree LED units is connected to the anode of the next or second LED 831.As for the remaining LEDs 831 are also connected in the same way.Accordingly, all the LEDs 831 of the three LED units are connected toform the mesh as shown in FIG. 11B.

In this embodiment, the length 836 of a portion of each conductive part839 that connects to the anode of an LED 831 is smaller than the length837 of another portion of each conductive part 839 that connects to thecathode of an LED 831. This makes the area of the latter portionconnecting to the cathode larger than that of the former portionconnecting to the anode. Moreover, the length 837 may be smaller than alength 838 of a portion of each conductive part 839 that connects thecathode of an LED 831 and the anode of the next LED 831 in two adjacentLED sets 833. This makes the area of the portion of each conductive part839 that connects a cathode and an anode larger than the area of anyother portion of each conductive part 839 that connects to only acathode or an anode of an LED 831. Due to the length differences andarea differences, this layout structure improves heat dissipation of theLEDs 831.

In some embodiments, the positive conductive line 834 includes alengthwise portion 834 a, and the negative conductive line 835 includesa lengthwise portion 835 a, which are conducive to make the LED modulehave a positive “+” connective portion and a negative “−” connectiveportion at each of the two ends of the LED module, as shown in FIG. 11C.Such a layout structure allows for coupling any of other circuits of thepower supply module of the LED lamp, including e.g. the filteringcircuit 520 and the rectifying circuits 510 and 540, to the LED modulethrough the positive connective portion and/or the negative connectiveportion at each or both ends of the LED lamp. Thus the layout structureincreases the flexibility in arranging actual circuits in the LED lamp.

FIG. 11D is a plan view of a circuit layout of the LED module accordingto another embodiment. Referring to FIG. 11D, in this embodiment,multiple LEDs 931 are connected in the same way as described in FIG.11A, and three LED units each including 7 LEDs 931 are assumed in theLED module 630 and described as follows for illustration. A positiveconductive line 934 and a negative conductive line 935 are to receive adriving signal for supplying power to the LEDs 931. For example, thepositive conductive line 934 may be coupled to the filtering outputterminal 521 of the filtering circuit 520 described above, and thenegative conductive line 935 is coupled to the filtering output terminal522 of the filtering circuit 520, so as to receive a filtered signal.For the convenience of illustration, all seven LEDs 931 of each of thethree LED units are grouped as an LED set 932 in FIG. 11D. Thus thereare three LED sets 932 corresponding to the three LED units.

The positive conductive line 934 connects the anode on the left side ofthe first or leftmost LED 931 of each of the three LED sets 932. Thenegative conductive line 935 connects the cathode on the right side ofthe last or rightmost LED 931 of each of the three LED sets 932. In eachLED set 932 of each two adjacent LEDs 931, the LED 931 on the left has acathode connected by a conductive part 939 to an anode of the LED 931 onthe right. By such a layout, the LEDs 931 of each LED set 932 areconnected in series.

In some embodiments, the conductive part 939 may be used to connect ananode and a cathode of two consecutive LEDs 931 respectively. Thenegative conductive line 935 connects the cathode of the last orrightmost LED 931 of each of the three LED sets 932. And the positiveconductive line 934 connects the anode of the first or leftmost LED 931of each of the three LED sets 932. Therefore, as shown in FIG. 11D, thelength of the conductive part 939 is larger than that of the portion ofnegative conductive line 935 connecting to a cathode, which length isthen larger than that of the portion of positive conductive line 934connecting to an anode. For example, the length 938 of the conductivepart 939 may be larger than the length 937 of the portion of negativeconductive line 935 connecting a cathode of an LED 931, which length 937is then larger than the length 936 of the portion of the positiveconductive line 934 connecting an anode of an LED 931. Such a layoutstructure improves heat dissipation of the LEDs 931 in LED module 630.

The positive conductive line 934 may include a lengthwise portion 934 a,and the negative conductive line 935 may include a lengthwise portion935 a, which are conducive to make the LED module have a positive “+”connective portion and a negative “−” connective portion at each of thetwo ends of the LED module, as shown in FIG. 11D. Such a layoutstructure allows for coupling any of other circuits of the power supplymodule of the LED lamp, including e.g. the filtering circuit 520 and therectifying circuits 510 and 540, to the LED module through the positiveconnective portion 934 a and/or the negative connective portion 935 a ateach or both ends of the LED lamp. Thus the layout structure increasesthe flexibility in arranging actual circuits in the LED lamp.

Further, the circuit layouts as shown in FIGS. 11C and 11D may beimplemented with a bendable circuit sheet or substrate, or may be aflexible circuit board depending on its specific construction. Forexample, the bendable circuit sheet may comprise one conductive layerwhere the positive conductive line 834, the positive lengthwise portion834 a, the negative conductive line 835, the negative lengthwise portion835 a, and the conductive parts 839 shown in FIG. 11C, and the positiveconductive line 934, the positive lengthwise portion 934 a, the negativeconductive line 935, the negative lengthwise portion 935 a, and theconductive parts 939 shown in FIG. 11D are formed by the method ofetching.

FIG. 11E is a plan view of a circuit layout of the LED module accordingto another embodiment. Referring to FIG. 11E, the connectionrelationship of the LEDs 1031 is the same as FIG. 11B. The configurationof the positive conductive line and the negative conductive line (notshown) and the connection relationship between the conductive lines andother circuits is substantially the same as FIG. 11D. The differencebetween the present embodiment and the above embodiments is that theLEDs 1031 are modified to be arranged in the longitudinal direction(i.e., the positive and negative electrodes of each LEDs are disposedalong the direction perpendicular to the lead extension direction) fromthe transverse direction such as arrangement of the LEDs 831 shown inFIG. 11C (i.e., the positive and negative electrodes of each LEDs aredisposed along the lead extension direction), and the connectionconfiguration of the present embodiment are correspondingly adjusted dueto the arrangement direction.

Specifically, taking a conductive part 1039_2 for example, theconductive part 1039_2 includes a first long-side portion having a width1037, a second long-side portion having a width 1038 which is greaterthan the width of the first long-side portion, and a transition portionconnecting the first and the second long-side portions. The conductivepart 1039_2 can be formed in a right-angled Z shape, which means thejoints of each long-side portions and the transition portion areperpendicular. The first long-side portion of the conductive part 1039_2and the second long-side portion of the adjacent conductive part 1039_3are correspondingly disposed; similarly, the second long-side portion ofthe conductive part 1039_2 and the first long-side portion of theadjacent conductive part 1039_1 are correspondingly disposed. Accordingto the configuration described above, the conductive part 1039 isarranged along the extension direction of the long-side portions, andthe first long-side portion of each conductive parts 1039 and the secondlong-side portion of each adjacent conductive parts 1039 arecorrespondingly disposed; similarly, the second long-side portion ofeach conductive parts 1039 and the first long-side portion of eachadjacent conductive parts 1039 are correspondingly disposed. Therefore,each of the conductive parts 1039 can be formed as a wiringconfiguration having consistent width. The configuration of the otherconductive parts 1039 can be similar to the description of theconductive part 1039_2 described above.

The conductive part 1039 is taken as an example for explaining therelative configuration of the LEDs 1031 and the conductive parts 1039 aswell. In the present embodiment, the positive electrodes of part of theLEDs 1031 (e.g., the four LEDs 1031 at the right-hand side) areconnected to the first long-side portion of the conductive part 1039_2and connected to each other via the first long-side portion; and thenegative electrodes of the part of the LEDs 1031 are connected to thesecond long-side portion of the adjacent conductive part 1039_3 andconnected to each other via the conductive part 1039_3. On the otherhand, the positive electrodes of another part of the LEDs 1031 (e.g.,the four LEDs 1031 at the left-hand side) are connected to the firstlong-side portion of the conductive part 1039_1, and the negativeelectrodes of the another part of the LEDs 1031 are connected to thesecond long-side portion of the conductive part 1039_2.

As can be seen in FIG. 11E, positive electrodes of the four LEDs 1031 atthe left-hand side are connected to each other via the conductive part1039_1, and the negative electrodes of the four LEDs 1031 at theleft-hand side are connected to each other via the conductive part1039_2. The positive electrodes of the four LEDs 1031 at the right-handside are connected to each other via the conductive part 1039_2, and thenegative electrodes of the four LEDs 1031 at the right-hand side areconnected to each other via the conductive part 1039_3. Since thenegative electrodes of the four LEDs 1031 at the left-hand side areconnected to the positive electrodes of the four LEDs 1031 at theright-hand side via the conductive part 1039_2, the left four LEDs 1031can be respectively referred to as the first LED in the four LED units,and the right four LEDs can be respectively referred to as the secondLED in the four LED units. The connection relationship of the other LEDscan be derived from the above configuration, so as to form the meshconnection as shown in FIG. 11B.

It should be noted that, compared to FIG. 11C, the LEDs 1031 of thepresent embodiment are modified to be arranged in the longitudinaldirection, such that the gap between the LEDs 1031 can be increased,which allows the effective width (which can be referred to the leadwidth) of the conductive part to be broadened. Therefore, the risk thatthe circuit is easily punctured when reconditioning the tube lamp can beavoided. Moreover, the short-circuit issue caused by the insufficientcoverage area of the copper foil between the LEDs 1031 when the LEDs1031 require to be arranged tightly can be removed or reduced.

On the other hand, by designing the width 1037 of the first long-sideportion connected to the positive electrodes smaller than the width 1038of the second long-side portion connected to the negative electrodes,the connection area of the negative electrodes on the LEDs 1031 islarger than the connection area of the positive electrodes on the LEDs1031. Thus, such wiring architecture facilitates heat dissipation of theLEDs.

FIG. 11F is a plan view of a circuit layout of the LED module accordingto another embodiment. Referring to FIG. 11F, the present embodiment isbasically similar to the embodiment illustrated in FIG. 11E, thedifference between those two embodiments is that the conductive part1139 is formed in a non-right-angled Z shape. In other words, in thepresent embodiment, the transition portion is formed by an obliquewiring, such that the joints of each long-side portion and thetransition portion are non-right angle. In the configuration of thepresent embodiment, in addition to increasing the gap between each LEDs1031 by disposing the LEDs 1031 along the longitudinal direction andthus the effective width of the conductive part can be broadened, theoblique wiring configuration may reduce the likelihood of thedisplacement or the offset when attaching the LED to an uneven solderingpad.

Specifically, according to the embodiment utilizing the flexible circuitboard as the LED light strip, the vertical conductive parts/leads (e.g.,portions that extend in a vertical direction in the configuration shownin FIG. 11C to FIG. 11E) cause a regular recessed/indented area at thetransition portion, so that the soldering spots of the LED solderingpads on the conductive parts are relatively on a raised position. Sincethe soldering spots are not a flat surface, it is hard to dispose theLEDs on the predetermined position when attaching the LEDs on the LEDlight strip. Thus, the present embodiment eliminates the recessed areaby adjusting the configuration of the vertical wiring to the obliquewiring, so that the strength of the copper foil of the whole wiring canbe uniform without a bulge or uneven situation at a specific positioncrossing the width of the LED light strip. Accordingly, the LEDs 1131can be attached on the conductive part easier, so as to enhance thereliability of tube lamp installation process. Also, since each of theLED units only passes the oblique wiring once on the LED light strip,the strength of the entire LED light strip can be greatly improved,therefore, the LED light strip can be prevented from being bent and thelength of the LED light strip can be shortened.

In addition, in an exemplary embodiment, the copper foil can be coveredaround the soldering pads of the LEDs 1131, so as to eliminate theoffset generated from attaching the LEDs 1131 and avoid theshort-circuit caused by the solder ball.

FIG. 11G is a plan view of a circuit layout of the LED module accordingto another embodiment. Referring to FIG. 11G, the present embodiment isbasically similar to the embodiment illustrated in FIG. 11C, thedifference between the two embodiments is that the correspondingconfiguration between the conductive parts 1239 (i.e., not the solderingpad position of the LEDs 1231) is modified to the oblique wiring.

In addition, according to the configuration of the present embodiment,the color temperature points CTP can be disposed between the LEDs 1231as shown in FIG. 11H. FIG. 11H is a plan view of a circuit layout of theLED module according to another embodiment. In the present embodiment,by disposing the color temperature points CTP between the LEDs in aconsistent manner, the corresponding color temperature points CTP on thedifferent conductive parts/LED units is on the same line and can be at asame relative location compared to each LED. As a result, the entire LEDmodule may only use several tapes for covering all of the colortemperature points CTP when soldering (e.g., use three tapes if therehas three color temperature points CTP on each conductive parts as shownin FIG. 11H). Therefore, the smoothness of the assembly process can beimproved and the assembly time can be saved as well.

FIG. 11I is a plan view of a circuit layout of the LED module accordingto another embodiment. Referring to FIG. 11I, the soldering pads b1 andb2 of the LED light strip are adapted to solder with the soldering padsof the power supply circuit board. The soldering pads of the presentembodiment can be adapted to the dual-end-single-pin configuration,which means the soldering pads at the same side will receive theexternal driving signal having the same polarity.

Specifically, the soldering pads b1 and b2 are connected to each othervia a S-shaped fuse FS, in which the fuse FS is constituted by, forexample, a thin wire. In one embodiment, the resistance of the thin wireis extremely low, so that the soldering pads b1 and b2 can be regardedas short-circuit. In the correct application situation, the solderingpads b1 and b2 receive the external driving signal having the samepolarity. Even if the soldering pads b1 and b2 are mis-connected to theexternal driving signal having opposite polarities, the fuse will befused (e.g. broken) by a large current passing through, therebypreventing the tube lamp from being damaged. In addition, the solderingpad b2 is at the floating state and the soldering pad b1 is stillconnected to the LED light strip after the fuse FS is fused, therefore,the LED light strip can be continuously used by receiving the externaldriving signal via the soldering pad b1.

In an exemplary embodiment, the thickness of the soldering pads b1 andb2 and the wiring connected to the soldering pads b1 and b2 at leastreach 0.4 mm, and the actual thickness can be selected from anythickness greater than 0.4 mm that is capable of implementing in the LEDlight strip design based on the understanding of one of the ordinaryskill in the art. Based on the verification result, once the thicknessof the soldering pads b1 and b2 and the connection wire reach 0.4 mm,even if the copper foil at the soldering pads b1 and b2 is broken whenthe soldering pads b1 and b2 are connected to the power supply circuitboard and disposed into the lamp tube, the copper foil on the peripheryof the soldering pads b1 and b2 can also connect the LED light strip tothe circuit on the power supply circuit board, so that the tube lamp canwork normally.

In addition, in another exemplary embodiment, the positions where thepads b1 and b2 on the LED light strip are disposed cause the pads b1 andb2 to have a gap from the edge of the LED light strip. Through the gapconfiguration, a fault-tolerant space can be enhanced when bonding thepower circuit board and the LED light strip.

FIG. 11J is a schematic view of a power pad according to an embodimentof the present invention. Referring to FIG. 11J, the power supplycircuit board has, for example, three pads a1, a2, and a3, and the powersupply circuit board can be a printed circuit board (PCB), however, thepresent invention is not limited thereto. There are a plurality throughholes hp disposed on each of the pads a1, a2 and a3. During the weldingprocess, the soldering material (e.g., soldering tin) is filled with atleast one of the through holes hp so that the soldering pads a1 to a3 onthe power supply circuit board (herein described as an after “powersoldering pad”) are connected to the pad on the LED light strip(hereinafter “LED soldering pad”). Herein, the LED light strip is, forexample, a flexible circuit board. It should be noted that in someembodiments, a flexible circuit board has a higher rigidity than abendable circuit sheet or flexible tape or ribbon. For example, aflexible circuit board may substantially maintain its shape whensupported by one or two hands of a person, whereas a flexible orbendable circuit sheet, tape, or ribbon may collapse or coil and thussignificantly changes shape when supported by one or two hands. Both aflexible circuit board and bendable circuit sheet may be bent ordeformed, but the flexible circuit board may be bent by applying aforce, whereas a bendable circuit sheet, when held, may bend on its ownwithout the application of any force.

Due to the through holes hp, the contact area between the solder and thepower soldering pads a1 to a3, and thus the adhesion force between thepower soldering pads a1 to a3 and the LED soldering pad can be enhanced.In addition, duo to the arrangement of the through holes hp, the heatdissipation area can be increased, and the terminal characteristic ofthe tube lamp can be improved. In the present embodiment, the number ofthe through holes on each power soldering pads is selected, for example,to be 7 or 9. If the configuration of 7 through holes being selected,the arrangement of the through holes hp can be that 6 through holes arearranged on a circumference on the pad, and the remaining is disposed onthe center of the circle. If the configuration of 9 through holes beingselected, the arrangement of the through holes hp can be arranged in a3×3 array. According to the selected arrangement, the effect of the heatdissipation can be preferably improved.

FIG. 11K is a plan view of a circuit layout of the LED module accordingto another embodiment. The layout structures of the LED module in FIGS.11K and 11C correspond to the same way of connecting the LEDs 831 asthose shown in FIG. 11B, but the layout structure in FIG. 11K comprisestwo conductive layers instead of only one conductive layer for formingthe circuit layout as shown in FIG. 11C. Referring to FIG. 11K, the maindifference from the layout in FIG. 11C is that the positive conductiveline 834 and the negative conductive line 835 have a lengthwise portion834 a and a lengthwise portion 835 a, respectively, that are formed in asecond conductive layer instead. The difference is elaborated asfollows.

In certain embodiments, referring to FIG. 7 again at the same time, abendable circuit sheet of the LED module includes a first conductivelayer 2 a and a second conductive layer 2 c electrically insulated fromeach other by a dielectric layer 2 b. Of the two conductive layers, thepositive conductive line 834, the negative conductive line 835, and theconductive parts 839 in FIG. 11E are formed in first conductive layer 2a by the method of etching for electrically connecting the plurality ofLED components 831 e.g. in a form of a mesh, whereas the positivelengthwise portion 834 a and the negative lengthwise portion 835 a areformed in second conductive layer 2 c by etching for electricallyconnecting (the filtering output terminal of) the filtering circuit.Further, the positive conductive line 834 and the negative conductiveline 835 in the first conductive layer 2 a have via points 834 b and viapoints 835 b, respectively, for connecting to second conductive layer 2c. And the positive lengthwise portion 834 a and the negative lengthwiseportion 835 a in second conductive layer 2 c have via points 834 c andvia points 835 c, respectively. The via points 834 b are positionedcorresponding to the via points 834 c, for connecting the positiveconductive line 834 and the positive lengthwise portion 834 a. The viapoints 835 b are positioned corresponding to the via points 835 c, forconnecting the negative conductive line 835 and the negative lengthwiseportion 835 a. An exemplary desirable way of connecting the twoconductive layers 2 a and 2 c is to form a hole connecting each viapoint 834 b and a corresponding via point 834 c, and to form a holeconnecting each via point 835 b and a corresponding via point 835 c,with the holes extending through the two conductive layers 2 a and 2 cand the dielectric layer 2 b in-between. And the positive conductiveline 834 and the positive lengthwise portion 834 a can be electricallyconnected by welding metallic part(s) through the connecting hole(s),and the negative conductive line 835 and the negative lengthwise portion835 a can be electrically connected by welding metallic part(s) throughthe connecting hole(s). It should be noted that, electrically speaking,the positive lengthwise portion 834 a and the negative lengthwiseportion 835 a in second conductive layer 2 c are part of the positiveconductive line 834 and negative conductive line 835 respectively.

Similarly, the layout structure of the LED module in FIG. 11D mayalternatively have the positive lengthwise portion 934 a and thenegative lengthwise portion 935 a disposed in a second conductive layerto constitute a two-layered layout structure.

The positive conductive lines (834 or 934) may be characterized asincluding two end terminals at opposite ends, a plurality of padsbetween the two end terminals and for contacting and/or supplying powerto LEDs (e.g., anodes of LEDs), and a wire portion, which may be anelongated conductive line extending along a length of an LED light stripand electrically connecting the two end terminals to the plurality ofpads. Similarly, the negative conductive lines (835 or 935) may becharacterized as including two end terminals at opposite ends, aplurality of pads between the two end terminals and for contactingand/or supplying power to LEDs (e.g., cathodes of LEDs), and a wireportion, which may be an elongated conductive line extending along alength of an LED light strip and electrically connecting the two endterminals to the plurality of pads.

The circuit layouts may be implemented for one of the exemplary LEDlight strips described previously, for example, to serve as a circuitboard or sheet for the LED light strip on which the LED light sourcesare disposed.

As described herein, an LED unit may refer to a single string of LEDsarranged in series, and an LED module may refer to a single LED unit, ora plurality of LED units connected to a same two nodes (e.g., arrangedin parallel). For example, the LED light strip 2 described above may bean LED module and/or LED unit.

In some embodiments, the thickness of the second conductive layer of atwo-layered bendable circuit sheet is, larger than that of the firstconductive layer in order to reduce the voltage drop or loss along eachof the positive lengthwise portion and the negative lengthwise portiondisposed in the second conductive layer. Compared to a one-layeredbendable circuit sheet, since a positive lengthwise portion and anegative lengthwise portion are disposed in a second conductive layer ina two-layer bendable circuit sheet, the width (between two lengthwisesides) of the two-layered bendable circuit sheet is or can be reduced.On the same fixture or plate in a production process, the number ofbendable circuit sheets each with a shorter width that can be laidtogether at most is larger than the number of bendable circuit sheetseach with a longer width that can be laid together at most. Thusadopting a bendable circuit sheet with a shorter width can increase theefficiency of production of the LED module. And reliability in theproduction process, such as the accuracy of welding position whenwelding (materials on) the LED components, can also be improved, becausea two-layer bendable circuit sheet can better maintain its shape.

As a variant of the above embodiments, a type of an exemplary LED tubelamp is provided that may have at least some of the electroniccomponents of its power supply module disposed on a light strip of theLED tube lamp. For example, the technique of printed electronic circuit(PEC) can be used to print, insert, or embed at least some of theelectronic components onto the LED light strip (e.g., as opposed tobeing on a separate circuit board connected to the LED light strip).

In one embodiment, all electronic components of the power supply moduleare disposed on the light strip. The production process may include orproceed with the following steps: preparation of the circuit substrate(e.g. preparation of a flexible printed circuit board); ink jet printingof metallic nano-ink; ink jet printing of active and passive components(as of the power supply module); drying/sintering; ink jet printing ofinterlayer bumps; spraying of insulating ink; ink jet printing ofmetallic nano-ink; ink jet printing of active and passive components (tosequentially form the included layers); spraying of surface bond pad(s);and spraying of solder resist against LED components. The productionprocess may be different, however, and still result in some or allelectronic components of the power supply module being disposed directlyon the LED light strip.

In certain embodiments, if all electronic components of the power supplymodule are disposed on the LED light strip, electrical connectionbetween the terminal pins of the LED tube lamp and the light strip maybe achieved by connecting the pins to conductive lines which are weldedwith ends of the light strip. In this case, another substrate forsupporting the power supply module is not required, thereby allowing ofan improved design or arrangement in the end cap(s) of the LED tubelamp. In some embodiments, (components of) the power supply module aredisposed at two ends of the light strip, in order to significantlyreduce the impact of heat generated from the power supply module'soperations on the LED components. Since no substrate other than thelight strip is used to support the power supply module in this case, thetotal amount of welding or soldering can be significantly reduced,improving the general reliability of the power supply module.

Another case is that some of all electronic components of the powersupply module, such as some resistors and/or smaller size capacitors,are printed onto the light strip, and some bigger size components, suchas some inductors and/or electrolytic capacitors, are disposed in theend cap(s). The production process of the light strip in this case maybe the same as that described above. And in this case disposing some ofall electronic components on the light strip is conducive to achieving areasonable layout of the power supply module in the LED tube lamp, whichmay allow of an improved design in the end cap(s).

As a variant embodiment of the above, electronic components of the powersupply module may be disposed on the LED light strip by a method ofembedding or inserting, e.g. by embedding the components onto a bendableor flexible light strip. In some embodiments, this embedding may berealized by a method using copper-clad laminates (CCL) for forming aresistor or capacitor; a method using ink related to silkscreenprinting; or a method of ink jet printing to embed passive components,wherein an ink jet printer is used to directly print inks to constitutepassive components and related functionalities to intended positions onthe light strip. Then through treatment by ultraviolet (UV) light ordrying/sintering, the light strip is formed where passive components areembedded. The electronic components embedded onto the light stripinclude for example resistors, capacitors, and inductors. In otherembodiments, active components also may be embedded. Through embeddingsome components onto the light strip, a reasonable layout of the powersupply module can be achieved to allow of an improved design in the endcap(s), because the surface area on a printed circuit board used forcarrying components of the power supply module is reduced or smaller,and as a result the size, weight, and thickness of the resulting printedcircuit board for carrying components of the power supply module is alsosmaller or reduced. Also in this situation since welding points on theprinted circuit board for welding resistors and/or capacitors if theywere not to be disposed on the light strip are no longer used, thereliability of the power supply module is improved, in view of the factthat these welding points are most liable to (cause or incur) faults,malfunctions, or failures. Further, the length of conductive linesneeded for connecting components on the printed circuit board istherefore also reduced, which allows of a more compact layout ofcomponents on the printed circuit board thus improving thefunctionalities of these components.

As mentioned above, electronic components of the power supply module 5or 250 may be disposed either on the light strip 2 or on a circuit board(such as a printed circuit board) in the end cap(s) of one or two endsof the lamp tube. For improving benefits or advantages of embodiments ofthe power supply module or the general LED tube lamp, in someembodiments, capacitor(s) in the power supply module may be chipcapacitor(s), such as multilayer ceramic chip capacitor(s), disposedeither on the light strip 2 or on the short circuit board 253. However,such disposed chip capacitor(s) in use is likely to produce or incurdistinct noise due to piezoelectric effects, which may adversely affectthe comfort level of using the LED tube lamp by consumers. To addressand reduce this problem, in the LED tube lamp of this disclosure, a holeor groove may be disposed (directly) below the chip capacitor bydrilling or boring, to significantly reduce the noise by changing thevibration system formed under piezoelectric effects between the chipcapacitor and the circuit board carrying the chip capacitor. The shapeof the circumference of the hole or groove may be substantially closeto, for example, a circle or round, an oval or ellipse, or a rectangle.In some embodiments, the hole or groove is formed in a conductive orwire layer in the light strip 2, or in the short circuit board 253 inthe end cap(s), and (directly) below the chip capacitor.

Next, methods to produce embedded capacitors and resistors are explainedas follows.

Usually, methods for manufacturing embedded capacitors employ or involvea concept called distributed or planar capacitance. The manufacturingprocess may include the following step(s). On a substrate of a copperlayer a very thin insulation layer is applied or pressed, which is thengenerally disposed between a pair of layers including a power conductivelayer and a ground layer. The very thin insulation layer makes thedistance between the power conductive layer and the ground layer veryshort. A capacitance resulting from this structure can also be realizedby a conventional technique of a plated-through hole. Basically, thisstep is used to create this structure comprising a big parallel-platecapacitor on a circuit substrate.

Of products of high electrical capacity, certain types of productsemploy distributed capacitances, and other types of products employseparate embedded capacitances. Through putting or adding a highdielectric-constant material, such as barium titanate, into theinsulation layer, the high electrical capacity is achieved.

A usual method for manufacturing embedded resistors employ conductive orresistive adhesive. This may include, for example, a resin to whichconductive carbon or graphite is added, which may be used as an additiveor filler. The additive resin is silkscreen printed to an objectlocation, and is then after treatment laminated inside the circuitboard. The resulting resistor is connected to other electroniccomponents through plated-through holes or microvias. Another method iscalled Ohmega-Ply, by which a two metallic layer structure of a copperlayer and a thin nickel alloy layer constitutes a layer resistorrelative to a substrate. Then through etching the copper layer andnickel alloy layer, different types of nickel alloy resistors withcopper terminals can be formed. These types of resistor are eachlaminated inside the circuit board.

In an embodiment, conductive wires/lines are directly printed in alinear layout on an inner surface of the LED glass lamp tube, with LEDcomponents directly attached on the inner surface and electricallyconnected by the conductive wires. In some embodiments, the LEDcomponents in the form of chips are directly attached over theconductive wires on the inner surface, and connective points are atterminals of the wires for connecting the LED components and the powersupply module. After being attached, the LED chips may have fluorescentpowder applied or dropped thereon, for producing white light or light ofother color by the operating LED tube lamp.

In some embodiments, luminous efficacy of the LED or LED component is 80lm/W or above, and in some embodiments, it may be 120 lm/W or above.Certain more optimal embodiments may include a luminous efficacy of theLED or LED component of 160 lm/W or above. White light emitted by an LEDcomponent in the invention may be produced by mixing fluorescent powderwith the monochromatic light emitted by a monochromatic LED chip. Thewhite light in its spectrum has major wavelength ranges of 430-460 nmand 550-560 nm, or major wavelength ranges of 430-460 nm, 540-560 nm,and 620-640 nm.

FIG. 12A is a block diagram of a power supply module in an LED lampaccording to an embodiment. As shown in FIG. 12A, the power supplymodule of the LED lamp includes a rectifying circuit 510, a filteringcircuit 520, and may further include some parts of an LED lightingmodule 530. The LED lighting module 530 in this embodiment comprises adriving circuit 1530 and an LED module 630. The driving circuit 1530comprises a DC-to-DC converter circuit, and is coupled to the filteringoutput terminals 521 and 522 to receive a filtered signal and thenperform power conversion for converting the filtered signal into adriving signal at the driving output terminals 1521 and 1522. The LEDmodule 630 is coupled to the driving output terminals 1521 and 1522 toreceive the driving signal for emitting light. In some embodiments, thecurrent of LED module 630 is stabilized at an objective current value.Descriptions of this LED module 630 can be the same as those providedabove with reference to FIGS. 11A-11K.

Referring to FIGS. 11A and 12A, under the configuration where thedriving circuit 1530 is included in the LED lighting module 530, thepositive terminal of the LED module 630 is changed from being connectedto the first filtering output terminal 521 to being connected to thefirst driving output terminal 1521, and the negative terminal of the LEDmodule 630 is changed from being connected to the second filteringoutput terminal 522 to being connected to the second driving outputterminal 1522.

In some embodiments, the first driving output terminal 1521 connected tothe positive terminal of the LED module 630 (i.e., the positiveelectrode of the LED units 632 or the anode of the first one of the LEDs631 in a column) is a DC power output terminal of the driving circuit1530, and the second driving output terminal 1522 connected to thenegative terminal of the LED module 630 (i.e., the negative electrode ofthe LED units 632 or the cathode of the last one of the LEDs 631 in acolumn) is a ground terminal/reference terminal of the driving circuit1530. Therefore, in one embodiment, the LED module 630 is coupledbetween the DC power output terminal and the ground/reference terminalof the driving circuit 1530.

In some embodiments, one of the first and the second driving outputterminals 1521 and 1522 is the DC power output terminal of the drivingcircuit 1530, and the other one of the first and the second drivingoutput terminals 1521 and 1522 is a DC power input terminal of thedriving circuit 1530. In this manner, the LED module 630 is coupledbetween the DC power input terminal and the DC power output terminal ofthe driving circuit 1530.

It should be noted that, the connection embodiments of the LED module630 described above is not limited to being utilized in a tube lamp. Theconnection embodiments can be applied to any kind of LED lamp directlypowered by the mains electricity/commercial electricity (i.e., the ACpower without passing a ballast), such as an LED bulb, an LED filamentlamp, an integrated LED lamp, etc. The invention is not limited to thesespecific examples.

In some embodiments, the LED lighting module 530 shown in FIG. 8D mayinclude the driving circuit 1530 and the LED module 630 as shown in FIG.12A. Thus, the power supply module for the LED lamp in the presentembodiment can be applied to the single-end power supply structure, suchas LED light bulbs, personal area lights (PAL), and so forth.

FIG. 12B is a block diagram of the driving circuit according to anembodiment. Referring to FIG. 12B, a driving circuit includes acontroller 1531, and a conversion circuit 1532 for power conversionbased on a current source, for driving the LED module to emit light. Theconversion circuit 1532 includes a switching circuit 1535 (also known asa power switch) and an energy storage circuit 1538. And the conversioncircuit 1532 is coupled to the filtering output terminals 521 and 522 toreceive and then convert a filtered signal, under the control by thecontroller 1531, into a driving signal at the driving output terminals1521 and 1522 for driving the LED module. Under the control by thecontroller 1531, the driving signal output by the conversion circuit1532 comprises a steady current, making the LED module emitting steadylight.

The operation of the driving circuit 1530 is further described based onthe signal waveform illustrated in FIGS. 12C to 12F. FIGS. 12C-12F aresignal waveform diagrams of exemplary driving circuits according to someexemplary embodiments, in which FIGS. 12C and 12D illustrate the signalwaveform and the control condition when the driving circuit 1530 isoperated in a Continuous-Conduction Mode (CCM) and FIGS. 12E and 12Fillustrate the signal waveform and the control condition when thedriving circuit 1530 is operated in a Discontinuous-Conduction Mode(DCM). In signal waveform diagrams, the horizontal axis represents time(represent by a symbol “t”), and the vertical axis represents a voltageor current value (depending on the type of the signal).

The controller 1531 can be, for example, a constant current controllerwhich can generate a lighting control signal Sic and adjust the dutycycle of the lighting control signal Sic based on a current detectionsignal Sdet, so that the switch circuit 1535 is turned on or off inresponse to the lighting control signal Sic. The energy storage circuit1538 is repeatedly charged and discharged according to the on/off stateof the switch circuit 1530, so that the driving current ILED received bythe LED module 630 can be stably maintained at a predetermined currentvalue Ipred. In some embodiments, the lighting control signal Sic mayhave fixed signal period Tlc and signal amplitude, and the pulse-on time(also known as the pulse width) of each signal period Tlc, such as Ton1,Ton2 and Ton3, can be adjusted according to the control requirement. Inthe present embodiment, the duty cycle of the lighting control signalSic represents a ratio of the pulse-on time and the signal period Tlc.For example, when the pulse-on time Ton1 is 40% of the signal periodTlc, the duty cycle of the lighting control signal Sic under the firstsignal period Tlc is 0.4.

In addition, the signal level of the current detection signal mayrepresent the magnitude of the current flowing through the LED module630, or represent the magnitude of the current flowing through theswitching circuit 1535; the present invention is not limited thereto.

Referring to FIGS. 12B and 12C, FIG. 12C illustrates the signal waveformvariation of the driving circuit 1530 during a plurality of signalperiods Tlc when the driving current ILED is smaller than thepredetermined current value Ipred. Specifically, under the first signalperiod Tlc, the switching circuit 1535 is turned on during the pulse-ontime Ton1 in response to the high level voltage of the lighting controlsignal Sic. In the meantime, the conversion circuit 1532 provides thedriving current ILED to the LED module 630 according to an input powerreceived from the first and the second filtering output terminals 521and 522, and further charges the energy storage circuit 1538 via theturned-on switch circuit 1535, so that the current IL flowing throughthe energy storage circuit 1538 gradually increases. In this manner,during the pulse-on time Ton1, the energy storage circuit 1538 ischarged in response to the input power received from the first and thesecond filtering output terminals 521 and 522.

After the pulse-on time Ton1, the switch circuit 1535 is turned off inresponse to the low level voltage of the lighting control signal Sic.During a cut-off period of the switch circuit 1535, the input poweroutput from the first and the second filtering output terminals 521 and522 would not be provided to the LED module 630, and the driving currentILED is dominated by the energy storage circuit 1538 (i.e., the drivingcurrent ILED is generated by the energy storage circuit 1538 bydischarging). Due to the energy storage circuit 1538 discharging duringthe cut-off period, the current IL is gradually decreased. Therefore,even when the lighting control signal Sic is at the low level (i.e., thedisable period of the lighting control signal Sic), the driving circuit1530 continuously supply power to the LED module 630 by discharging theenergy storage circuit 1538. In this embodiment, no matter whether theswitch circuit 1535 is turned on or off, the driving circuit 1530continuously provides a stable driving current ILED to the LED module630, and the current value of the driving current ILED is I1 during thefirst signal period Tlc.

Under the first signal period Tlc, the controller 1531 determines thecurrent value I1 of the driving current ILED is smaller than thepredetermined current value Ipred, so that the pulse-on time of thelighting control signal Sic is adjusted to Ton2 when entering the secondsignal period Tlc. The length of the pulse-on time Ton2 equals to thelength of the pulse-on time Ton1 plus a unit period t1.

Under the second signal period Tlc, the operation of the switch circuit1535 and the energy storage circuit 1538 are similar to the operationunder the first signal period Tlc. The difference of the operationbetween the first and the second signal periods Tlc is the energystorage circuit 1538 has relatively longer charging time and shorterdischarging time since the pulse-on time Ton2 is longer than pulse-ontime Ton1, Therefore, the average current value of the driving currentILED under the second signal period Tlc is increased to a current valueI2 closer to the predetermined current value Ipred.

Similarly, since the current value I2 of the driving current ILED isstill smaller than the predetermined current value Ipred, the controller1531 further adjusts, under the third signal period Tlc, the pulse-ontime of the lighting control signal Sic to Ton3, in which the length ofthe pulse-on time Ton3 equals to the length of the pulse-on time Ton2plus the unit period t1. Under the third signal period Ton3, theoperation of the switch circuit 1535 and the energy storage circuit 1538are similar to the operation under the first and the second signalperiods Tlc. Due to the pulse-on time Ton3 being further increased incomparison with the pulse-on time Ton1 and Ton2, the current value ofthe driving current ILED is increased to I3, and substantially reachesthe predetermined current value Ipred. Since the current value I3 of thedriving current ILED has reached the predetermined current value Ipred,the controller 1531 maintains the same duty cycle after the third signalperiod Tlc, so that the driving current ILED can be substantiallymaintained at the predetermined current value Ipred.

Referring to FIGS. 12B and 12D, FIG. 12D illustrates the signal waveformvariation of the driving circuit 1530 during a plurality of signalperiods Tlc when the driving current ILED is larger than thepredetermined current value Ipred. Specifically, under the first signalperiod Tlc, the switching circuit 1535 is turned on during the pulse-ontime Ton1 in response to the high level voltage of the lighting controlsignal Sic. In the meantime, the conversion circuit 1532 provides thedriving current ILED to the LED module 630 according to an input powerreceived from the first and the second filtering output terminals 521and 522, and further charges the energy storage circuit 1538 via theturned-on switch circuit 1535, so that the current IL flowing throughthe energy storage circuit 1538 gradually increases. As a result, duringthe pulse-on time Ton1, the energy storage circuit 1538 is charged inresponse to the input power received from the first and the secondfiltering output terminals 521 and 522.

After the pulse-on time Ton1, the switch circuit 1535 is turned off inresponse to the low level voltage of the lighting control signal Sic.During a cut-off period of the switch circuit 1535, the input poweroutput from the first and the second filtering output terminals 521 and522 would not be provided to the LED module 630, and the driving currentILED is dominated by the energy storage circuit 1538 (i.e., the drivingcurrent ILED is generated by the energy storage circuit 1538 bydischarging). Due to the energy storage circuit 1538 discharging duringthe cut-off period, the current IL is gradually decreased. Therefore,even when the lighting control signal Sic is at the low level (i.e., thedisable period of the lighting control signal Sic), the driving circuit1530 continuously supplies power to the LED module 630 by dischargingthe energy storage circuit 1538. Accordingly, no matter whether theswitch circuit 1535 is turned on or turned off, the driving circuit 1530continuously provides a stable driving current ILED to the LED module630, and the current value of the driving current ILED is I4 during thefirst signal period Tlc.

Under the first signal period Tlc, the controller 1531 determines thecurrent value I4 of the driving current ILED is larger than thepredetermined current value Ipred, so that the pulse-on time of thelighting control signal Sic is adjusted to Ton2 when entering the secondsignal period Tlc. The length of the pulse-on time Ton2 equals to thelength of the pulse-on time Ton1 minus the unit period t1.

Under the second signal period Tlc, the operation of the switch circuit1535 and the energy storage circuit 1538 are similar to the operationunder the first signal period Tlc. The difference of the operationbetween the first and the second signal periods Tlc is the energystorage circuit 1538 has relatively shorter charging time and longerdischarging time since the pulse-on time Ton2 is shorter than pulse-ontime Ton1. Therefore, the average current value of the driving currentILED under the second signal period Tlc is decreased to a current valueI5 closer to the predetermined current value Ipred.

Similarly, since the current value I5 of the driving current ILED isstill larger than the predetermined current value Ipred, the controller1531 further adjusts, under the third signal period Tlc, the pulse-ontime of the lighting control signal Slc to Ton3, in which the length ofthe pulse-on time Ton3 equals to the length of the pulse-on time Ton2minus the unit period t1. Under the third signal period Tlc, theoperation of the switch circuit 1535 and the energy storage circuit 1538are similar to the operation under the first and the second signalperiods Tlc. Since the pulse-on time Ton3 is further decreased incomparison with the pulse-on time Ton1 and Ton2, the current value ofthe driving current ILED is decreased to I6, so that the driving currentILED substantially reaches the predetermined current value Ipred. Sincethe current value I6 of the driving current ILED has reached thepredetermined current value Ipred, the controller 1531 maintains thesame duty cycle after the third signal period Tlc, so that the drivingcurrent ILED can be substantially maintained on the predeterminedcurrent value Ipred.

According to the above operations, the driving circuit 1530 may adjust,by a stepped approach, the pulse-on time/pulse width of the lightingcontrol signal Slc, so that the driving current ILED is graduallyadjusted to be close to the predetermined current value Ipred.Therefore, the constant current output can be realized.

In the present embodiment, the driving circuit 1530 is operated in CCMfor example, which means the energy storage circuit 1538 will not bedischarged to zero current (i.e., the current IL will not be decreasedto zero) during the cut-off period of the switch circuit 1535. Byutilizing the driving circuit 1530 operating in CCM to provide power tothe LED module 630, the power provided to the LED module 630 can be morestable and has a low ripple.

The control operation of the driving circuit 1530 operating in DCM willbe described below. Referring to FIGS. 12B and 12E, the operation andthe signal waveform of the driving circuit 1530 illustrated in FIG. 12Eare similar to the FIG. 12C. The difference between the FIGS. 12C and12E is that the driving circuit 1530 operates in DCM, so that the energystorage circuit 1538 discharges, during the pulse-off time of thelighting control signal Slc, to zero current (i.e., the current ILequals to zero) and then re-charges in the next signal period Tlc. Theother operation of the driving circuit 1530 can be referred to theembodiments of FIG. 12C, and will not be described in detail herein.

Referring to FIGS. 12B and 12F, the operation and the signal waveform ofthe driving circuit 1530 illustrated in FIG. 12F are similar to that ofFIG. 12D. The difference between the FIGS. 12D and 12F is that thedriving circuit 1530 operates in DCM, so that the energy storage circuit1538 discharges, during the pulse-off time of the lighting controlsignal Slc, to zero current (i.e., the current IL decreases to zero) andthen re-charges in the next signal period Tlc. The other operation ofthe driving circuit 1530 can be referred to the embodiments of FIG. 12D,and will not be described in detail herein.

By utilizing the driving circuit 1530 operating in DCM to provide powerto the LED module 630, the driving circuit 1530 may have lower powerconsumption, so as to obtain higher power conversion efficiency.

In addition, the embodiments of the power conversion operation describedabove are not limited to be utilized in a tube lamp. The embodiments canbe applied to any kind of LED lamp directly powered by the mainselectricity/commercial electricity (i.e., the AC power without passing aballast), such as an LED bulb, an LED filament lamp, an integrated LEDlamp or etc. The invention is not limited to these specific examples.

FIG. 12G is a schematic diagram of the driving circuit according to anembodiment. Referring to FIG. 12G, a driving circuit 1630 in thisembodiment comprises a buck DC-to-DC converter circuit having acontroller 1631 and a converter circuit. The converter circuit includesan inductor 1632, a diode 1633 for “freewheeling” of current, acapacitor 1634, and a switch 1635. The driving circuit 1630 is coupledto the filtering output terminals 521 and 522 to receive and thenconvert a filtered signal into a driving signal for driving an LEDmodule connected between the driving output terminals 1521 and 1522.

In this embodiment, the switch 1635 includes a metal-oxide-semiconductorfield-effect transistor (MOSFET) and has a first terminal coupled to theanode of freewheeling diode 1633, a second terminal coupled to thefiltering output terminal 522, and a control terminal coupled to thecontroller 1631 used for controlling current conduction or cutoffbetween the first and second terminals of switch 1635. The drivingoutput terminal 1521 is connected to the filtering output terminal 521,and the driving output terminal 1522 is connected to an end of theinductor 1632, which has another end connected to the first terminal ofswitch 1635. The capacitor 1634 is coupled between the driving outputterminals 1521 and 1522 to stabilize the voltage between the drivingoutput terminals 1521 and 1522. The freewheeling diode 1633 has acathode connected to the driving output terminal 1521.

Next, a description follows as to an exemplary operation of the drivingcircuit 1630.

The controller 1631 is configured for determining when to turn theswitch 1635 on (in a conducting state) or off (in a cutoff state)according to a current detection signal S535 and/or a current detectionsignal S531. For example, in some embodiments, the controller 1631 isconfigured to control the duty cycle of switch 1635 being on and switch1635 being off in order to adjust the size or magnitude of the drivingsignal. The current detection signal S535 represents the magnitude ofcurrent through the switch 1635. The current detection signal S531represents the magnitude of current through the LED module coupledbetween the driving output terminals 1521 and 1522. The controller 1631may control the duty cycle of the switch 1635 being on and off, basedon, for example, a magnitude of a current detected based on currentdetection signal S531 or S535. As such, when the magnitude is above athreshold, the switch may be off (cutoff state) for more time, and whenmagnitude goes below the threshold, the switch may be on (conductingstate) for more time. According to any of current detection signal S535and current detection signal S531, the controller 1631 can obtaininformation on the magnitude of power converted by the convertercircuit. When the switch 1635 is switched on, a current of a filteredsignal is input through the filtering output terminal 521, and thenflows through the capacitor 1634, the driving output terminal 1521, theLED module, the inductor 1632, and the switch 1635, and then flows outfrom the filtering output terminal 522. During this flowing of current,the capacitor 1634 and the inductor 1632 are performing storing ofenergy. On the other hand, when the switch 1635 is switched off, thecapacitor 1634 and the inductor 1632 perform releasing of stored energyby a current flowing from the freewheeling diode 1633 to the drivingoutput terminal 1521 to make the LED module continuing to emit light.

In some embodiments, the capacitor 1634 is an optional element, so itcan be omitted and is thus depicted in a dotted line in FIG. 12C. Insome application environments, the natural characteristic of an inductorto oppose instantaneous change in electric current passing through theinductor may be used to achieve the effect of stabilizing the currentthrough the LED module, thus omitting the capacitor 1634. It should benoted that, since the present embodiment utilizes the non-isolatingdriving circuit for performing power conversion, which means there is notransformer in the driving circuit, the switch 1635 is capable of beingcontrolled by detecting the magnitude of the current flowing through theswitch 1635 (e.g., the current detection signal S535). If the isolatingdriving circuit is utilized for performing power conversion, due to theLED module and the controller being isolated by a transformer, theswitch 1635 can merely be controlled by detecting the magnitude of thecurrent flowing through the LED module (e.g., the current detectionsignal S531). In addition, in one embodiment, when the isolating drivingcircuit is adopted, a detection resistor (not shown) is required fordetecting current flowing through the LED module, and a photo-coupler(not shown) is required for transmitting the detection result to thecontroller 1631 at the primary side as the basis of controlling theswitch 1635.

As described above, because the driving circuit 1630 is configured fordetermining when to turn a switch 1635 on (in a conducting state) or off(in a cutoff state) according to a current detection signal S535 and/ora current detection signal S531, the driving circuit 1630 can maintain astable current flow through the LED module. Therefore, the colortemperature may not change with current to some LED module, such aswhite, red, blue, green LED modules. For example, an LED can retain thesame color temperature under different illumination conditions. In someembodiments, because the inductor 1632 playing the role of theenergy-storing circuit releases the stored power when the switch 1635cuts off, the voltage/current flowing through the LED module remainsabove a predetermined voltage/current level so that the LED module maycontinue to emit light maintaining the same color temperature. In thisway, when the switch 1635 conducts again, the voltage/current flowingthrough the LED module does not need to be adjusted to go from a minimumvalue to a maximum value. Accordingly, the LED module lighting withflickering can be avoided, the entire illumination can be improved, thelowest conducting period can be smaller, and the driving frequency canbe higher.

FIG. 12H is a schematic diagram of the driving circuit according to anembodiment. Referring to FIG. 12H, a driving circuit 1730 in thisembodiment comprises a boost DC-to-DC converter circuit having acontroller 1731 and a converter circuit. The converter circuit includesan inductor 1732, a diode 1733 for “freewheeling” of current, acapacitor 1734, and a switch 1735. The driving circuit 1730 isconfigured to receive and then convert a filtered signal from thefiltering output terminals 521 and 522 into a driving signal for drivingan LED module coupled between the driving output terminals 1521 and1522.

The inductor 1732 has an end connected to the filtering output terminal521, and another end connected to the anode of freewheeling diode 1733and a first terminal of the switch 1735, which has a second terminalconnected to the filtering output terminal 522 and the driving outputterminal 1522. The freewheeling diode 1733 has a cathode connected tothe driving output terminal 1521. And the capacitor 1734 is coupledbetween the driving output terminals 1521 and 1522.

The controller 1731 is coupled to a control terminal of switch 1735, andis configured for determining when to turn the switch 1735 on (in aconducting state) or off (in a cutoff state), according to a currentdetection signal S535 and/or a current detection signal S531. When theswitch 1735 is switched on, a current of a filtered signal is inputthrough the filtering output terminal 521, and then flows through theinductor 1732 and the switch 1735, and then flows out from the filteringoutput terminal 522. During this flowing of current, the current throughthe inductor 1732 increases with time, with the inductor 1732 being in astate of storing energy, while the capacitor 1734 enters a state ofreleasing energy, making the LED module continuing to emit light. On theother hand, when the switch 1735 is switched off, the inductor 1732enters a state of releasing energy as the current through the inductor1732 decreases with time. In this state, the current through theinductor 1732 then flows through the freewheeling diode 1733, thecapacitor 1734, and the LED module, while the capacitor 1734 enters astate of storing energy.

In some embodiments, the capacitor 1734 is an optional element, so itcan be omitted and is thus depicted in a dotted line in FIG. 12D. Whenthe capacitor 1734 is omitted and the switch 1735 is switched on, thecurrent of inductor 1732 does not flow through the LED module, makingthe LED module not emit light; but when the switch 1735 is switched off,the current of inductor 1732 flows through the freewheeling diode 1733to reach the LED module, making the LED module emit light. Therefore, bycontrolling the time that the LED module emits light, and the magnitudeof current through the LED module, the average luminance of the LEDmodule can be stabilized to be above a defined value, thus alsoachieving the effect of emitting a steady light. It should be notedthat, since the present embodiment utilizes the non-isolating drivingcircuit for performing power conversion, which means there is notransformer in the driving circuit, the switch 1735 is capable of beingcontrolled by detecting the magnitude of the current flowing through theswitch 1735 (e.g., the current detection signal S535). If the isolatingdriving circuit is utilized for performing power conversion, due to theLED module and the controller being isolated by a transformer, themagnitude of the current flowing through the switch 1735 cannot be usedfor the reference of controlling the switch 1735.

As described above, because the controller 1731 included in the drivingcircuit 1730 is coupled to the control terminal of switch 1735, and isconfigured for determining when to turn a switch 1735 on (in aconducting state) or off (in a cutoff state), according to a currentdetection signal S535 and/or a current detection signal S531, thedriving circuit 1730 can maintain a stable current flow through the LEDmodule. Therefore, the color temperature may not change with current tosome LED modules, such as white, red, blue, or green LED modules. Forexample, an LED can retain the same color temperature under differentillumination conditions. In some embodiments, because the inductor 1732playing the role of the energy-storing circuit releases the stored powerwhen the switch 1735 cuts off, the voltage/current flowing through theLED module remains above a predetermined voltage/current level so thatthe LED module may continue to emit light maintaining the same colortemperature. In this way, when the switch 1735 conducts again, thevoltage/current flowing through the LED module does not need to beadjusted to go from a minimum value to a maximum value. Accordingly, theLED module lighting with flickering can be avoided, the entireillumination can be improved, the lowest conducting period can besmaller, and the driving frequency can be higher.

FIG. 12I is a schematic diagram of the driving circuit according to anexemplary embodiment. Referring to FIG. 12I, a driving circuit 1830 inthis embodiment comprises a buck DC-to-DC converter circuit having acontroller 1831 and a converter circuit. The converter circuit includesan inductor 1832, a diode 1833 for “freewheeling” of current, acapacitor 1834, and a switch 1835. The driving circuit 1830 is coupledto the filtering output terminals 521 and 522 to receive and thenconvert a filtered signal into a driving signal for driving an LEDmodule connected between the driving output terminals 1521 and 1522.

The switch 1835 has a first terminal coupled to the filtering outputterminal 521, a second terminal coupled to the cathode of freewheelingdiode 1833, and a control terminal coupled to the controller 1831 toreceive a control signal from the controller 1831 for controllingcurrent conduction or cutoff between the first and second terminals ofthe switch 1835. The anode of freewheeling diode 1833 is connected tothe filtering output terminal 522 and the driving output terminal 1522.The inductor 1832 has an end connected to the second terminal of switch1835, and another end connected to the driving output terminal 1521. Thecapacitor 1834 is coupled between the driving output terminals 1521 and1522 to stabilize the voltage between the driving output terminals 1521and 1522.

The controller 1831 is configured for controlling when to turn theswitch 1835 on (in a conducting state) or off (in a cutoff state)according to a current detection signal S535 and/or a current detectionsignal S531. When the switch 1835 is switched on, a current of afiltered signal is input through the filtering output terminal 521, andthen flows through the switch 1835, the inductor 1832, and the drivingoutput terminals 1521 and 1522, and then flows out from the filteringoutput terminal 522. During this flowing of current, the current throughthe inductor 1832 and the voltage of the capacitor 1834 both increasewith time, so the inductor 1832 and the capacitor 1834 are in a state ofstoring energy. On the other hand, when the switch 1835 is switched off,the inductor 1832 is in a state of releasing energy and thus the currentthrough it decreases with time. In this case, the current through theinductor 1832 circulates through the driving output terminals 1521 and1522, the freewheeling diode 1833, and back to the inductor 1832.

In some embodiments the capacitor 1834 is an optional element, so it canbe omitted and is thus depicted in a dotted line in FIG. 12E. When thecapacitor 1834 is omitted, no matter whether the switch 1835 is turnedon or off, the current through the inductor 1832 will flow through thedriving output terminals 1521 and 1522 to drive the LED module tocontinue emitting light. It should be noted that, since the presentembodiment utilizes the non-isolating driving circuit for performingpower conversion, which means there is no transformer in the drivingcircuit, the switch 1835 is capable of being controlled by detecting themagnitude of the current flowing through the switch 1835 (e.g., thecurrent detection signal S535). If the isolating driving circuit isutilized for performing power conversion, due to the LED module and thecontroller being isolated by a transformer, the magnitude of the currentflowing through the switch 1835 cannot be used for the reference ofcontrolling the switch 1835.

As described above, because the controller 1831 included in the drivingcircuit 1830 is configured for controlling when to turn a switch 1835 on(in a conducting state) or off (in a cutoff state) according to acurrent detection signal S535 and/or a current detection signal S531,the driving circuit 1730 can maintain a stable current flow through theLED module. Therefore, the color temperature may not change with currentto some LED modules, such as white, red, blue, or green LED modules. Forexample, an LED can retain the same color temperature under differentillumination conditions. In some embodiments, because the inductor 1832playing the role of the energy-storing circuit releases the stored powerwhen the switch 1835 cuts off, the voltage/current flowing through theLED module remains above a predetermined voltage/current level so thatthe LED module may continue to emit light maintaining the same colortemperature. In this way, when the switch 1835 conducts again, thevoltage/current flowing through the LED module does not need to beadjusted to go from a minimum value to a maximum value. Accordingly, theLED module lighting with flickering can be avoided, the entireillumination can be improved, the lowest conducting period can besmaller, and the driving frequency can be higher.

FIG. 12J is a schematic diagram of the driving circuit according to anexemplary embodiment. Referring to FIG. 12J, a driving circuit 1930 inthis embodiment comprises a buck DC-to-DC converter circuit having acontroller 1931 and a converter circuit. The converter circuit includesan inductor 1932, a diode 1933 for “freewheeling” of current, acapacitor 1934, and a switch 1935. The driving circuit 1930 is coupledto the filtering output terminals 521 and 522 to receive and thenconvert a filtered signal into a driving signal for driving an LEDmodule connected between the driving output terminals 1521 and 1522.

The inductor 1932 has an end connected to the filtering output terminal521 and the driving output terminal 1522, and another end connected to afirst end of the switch 1935. The switch 1935 has a second end connectedto the filtering output terminal 522, and a control terminal connectedto controller 1931 to receive a control signal from controller 1931 forcontrolling current conduction or cutoff of the switch 1935. Thefreewheeling diode 1933 has an anode coupled to a node connecting theinductor 1932 and the switch 1935, and a cathode coupled to the drivingoutput terminal 1521. The capacitor 1934 is coupled to the drivingoutput terminals 1521 and 1522 to stabilize the driving of the LEDmodule coupled between the driving output terminals 1521 and 1522.

The controller 1931 is configured for controlling when to turn theswitch 1935 on (in a conducting state) or off (in a cutoff state)according to a current detection signal S531 and/or a current detectionsignal S535. When the switch 1935 is turned on, a current is inputthrough the filtering output terminal 521, and then flows through theinductor 1932 and the switch 1935, and then flows out from the filteringoutput terminal 522. During this flowing of current, the current throughthe inductor 1932 increases with time, so the inductor 1932 is in astate of storing energy; but the voltage of the capacitor 1934 decreaseswith time, so the capacitor 1934 is in a state of releasing energy tokeep the LED module continuing to emit light. On the other hand, whenthe switch 1935 is turned off, the inductor 1932 is in a state ofreleasing energy and its current decreases with time. In this case, thecurrent through the inductor 1932 circulates through the freewheelingdiode 1933, the driving output terminals 1521 and 1522, and back to theinductor 1932. During this circulation, the capacitor 1934 is in a stateof storing energy and its voltage increases with time.

In some embodiments the capacitor 1934 is an optional element, so it canbe omitted and is thus depicted in a dotted line in FIG. 12F. When thecapacitor 1934 is omitted and the switch 1935 is turned on, the currentthrough the inductor 1932 doesn't flow through the driving outputterminals 1521 and 1522, thereby making the LED module not emit light.On the other hand, when the switch 1935 is turned off, the currentthrough the inductor 1932 flows through the freewheeling diode 1933 andthen the LED module to make the LED module emit light. Therefore, bycontrolling the time that the LED module emits light, and the magnitudeof current through the LED module, the average luminance of the LEDmodule can be stabilized to be above a defined value, thus alsoachieving the effect of emitting a steady light. It should be notedthat, since the present embodiment utilizes the non-isolating drivingcircuit for performing power conversion, which means there is notransformer in the driving circuit, the switch 1935 is capable of beingcontrolled by detecting the magnitude of the current flowing through theswitch 1935 (e.g., the current detection signal S535). If the isolatingdriving circuit is utilized for performing power conversion, due to theLED module and the controller being isolated by a transformer, themagnitude of the current flowing through the switch 1935 cannot be usedfor the reference of controlling the switch 1935.

As described above, because the controller 1931 included in the drivingcircuit 1930 is configured for controlling when to turn a switch 1935 on(in a conducting state) or off (in a cutoff state) according to acurrent detection signal S535 and/or a current detection signal S531,the driving circuit 1930 can maintain a stable current flow through theLED module. Therefore, the color temperature may not change with currentto some LED modules, such as white, red, blue, or green LED modules. Forexample, an LED can retain the same color temperature under differentillumination conditions. In some embodiments, because the inductor 1932playing the role of the energy-storing circuit releases the stored powerwhen the switch 1935 cuts off, the voltage/current flowing through theLED module remains above a predetermined voltage/current level so thatthe LED module may continue to emit light maintaining the same colortemperature. In this way, when the switch 1935 conducts again, thevoltage/current flowing through the LED module does not need to beadjusted to go from a minimum value to a maximum value. Accordingly, theLED module lighting with flickering can be avoided, the entireillumination can be improved, the lowest conducting period can besmaller, and the driving frequency can be higher.

With reference back to FIGS. 5 and 6, a short circuit board 253 includesa first short circuit substrate and a second short circuit substraterespectively connected to two terminal portions of a long circuit sheet251, and electronic components of the power supply module arerespectively disposed on the first short circuit substrate and thesecond short circuit substrate. The first short circuit substrate andthe second short circuit substrate may have roughly the same length, ordifferent lengths. In general, the first short circuit substrate (i.e.the right circuit substrate of short circuit board 253 in FIG. 5 and theleft circuit substrate of short circuit board 253 in FIG. 6) has alength that is about 30%-80% of the length of the second short circuitsubstrate (i.e. the left circuit substrate of short circuit board 253 inFIG. 5 and the right circuit substrate of short circuit board 253 inFIG. 6). In some embodiments the length of the first short circuitsubstrate is about ⅓-⅔ of the length of the second short circuitsubstrate. For example, in one embodiment, the length of the first shortcircuit substrate may be about half the length of the second shortcircuit substrate. The length of the second short circuit substrate maybe, for example in the range of about 15 mm to about 65 mm, depending onactual application occasions. In certain embodiments, the first shortcircuit substrate is disposed in an end cap at an end of the LED tubelamp, and the second short circuit substrate is disposed in another endcap at the opposite end of the LED tube lamp.

For example, capacitors of the driving circuit, such as the capacitors1634, 1734, 1834, and 1934 in FIGS. 12C-12F, in practical use mayinclude two or more capacitors connected in parallel. Some or allcapacitors of the driving circuit in the power supply module may bearranged on the first short circuit substrate of short circuit board253, while other components such as the rectifying circuit, filteringcircuit, inductor(s) of the driving circuit, controller(s), switch(es),diodes, etc. are arranged on the second short circuit substrate of shortcircuit board 253. Since the inductors, controllers, switches, etc. areelectronic components with higher temperature, arranging some or allcapacitors on a circuit substrate separate or away from the circuitsubstrate(s) of high-temperature components helps prevent the workinglife of capacitors (especially electrolytic capacitors) from beingnegatively affected by the high-temperature components, thus improvingthe reliability of the capacitors. Further, the physical separationbetween the capacitors and both the rectifying circuit and filteringcircuit also contributes to reducing the problem of EMI.

In certain exemplary embodiments, the conversion efficiency of thedriving circuits is above 80%. In some embodiments, the conversionefficiency of the driving circuits is above 90%. In still otherembodiments, the conversion efficiency of the driving circuits is above92%. The illumination efficiency of the LED lamps is above 120 lm/W. Insome embodiments, the illumination efficiency of the LED lamps is above160 lm/W. The illumination efficiency including the combination of thedriving circuits and the LED modules is above 120 lm/W*90%=108 lm/W. Insome embodiments, the illumination efficiency including the combinationof the driving circuits and the LED modules is above 160 lm/W*92%=147.21lm/W.

In some embodiments, the transmittance of the diffusion film in the LEDtube lamp is above 85%. As a result, in certain embodiments, theillumination efficiency of the LED lamps is above 108 lm/W*85%=91.8lm/W. In some embodiments, the illumination efficiency of the LED lampsis above 147.21 lm/W*85%=125.12 lm/W.

FIG. 13A is a block diagram of a power supply module in an LED tube lampaccording to an exemplary embodiment. Compared to that shown in FIG. 8D,the present embodiment comprises a rectifying circuit 510, a filteringcircuit 520, and a driving circuit 1530, and further comprises an overvoltage protection (OVP) circuit 1570. In this embodiment, a drivingcircuit 1530 and an LED module 630 compose the LED lighting module 530.The OVP circuit 1570 is coupled to the filtering output terminals 521and 522 for detecting the filtered signal. The OVP circuit 1570 clampsthe logic level of the filtered signal when determining the logic levelthereof higher than a defined OVP value. Hence, the OVP circuit 1570protects the LED lighting module 530 from damage due to an OVPcondition.

FIG. 13B is a schematic diagram of an overvoltage protection (OVP)circuit according to an exemplary embodiment. An OVP circuit 1670comprises a voltage clamping diode 1671, such as zener diode, coupled tothe filtering output terminals 521 and 522. The voltage clamping diode1671 is conducted to clamp a voltage difference at a breakdown voltagewhen the voltage difference of the filtering output terminals 521 and522 (i.e., the logic level of the filtered signal) reaches the breakdownvoltage. In some embodiments, the breakdown voltage may be in a range ofabout 40 V to about 100 V. In certain embodiments, the breakdown voltagemay be in a range of about 55 V to about 75V.

FIG. 14A is a block diagram of a power supply module in an LED tube lampaccording to an exemplary embodiment. Compared to that shown in FIG. 8D,the present embodiment comprises a rectifying circuit 510, a filteringcircuit 520, and a driving circuit 1530, and further comprises anauxiliary power module 2510. The auxiliary power module 2510 is coupledbetween the filtering output terminals 521 and 522. The auxiliary powermodule 2510 detects the filtered signal in the filtering outputterminals 521 and 522, and determines whether to provide an auxiliarypower to the filtering output terminals 521 and 522 based on thedetected result. When the supply of the filtered signal is stopped or alogic level (i.e., a voltage) thereof is insufficient, i.e., when adrive voltage for the LED module is below a defined voltage, theauxiliary power module provides auxiliary power to keep the LED lightingmodule 530 continuing to emit light. The defined voltage is determinedaccording to an auxiliary power voltage of the auxiliary power module2510.

FIG. 14B is a block diagram of a power supply module in an LED tube lampaccording to an exemplary embodiment. Compared to that shown in FIG.14A, the present embodiment comprises a rectifying circuit 510, afiltering circuit 520, and may further include some parts of an LEDlighting module 530, and an auxiliary power module 2510, and the LEDlighting module 530 further comprises a driving circuit 1530 and an LEDmodule 630. The auxiliary power module 2510 is coupled between thedriving output terminals 1521 and 1522. The auxiliary power module 2510detects the driving signal in the driving output terminals 1521 and1522, and determines whether to provide an auxiliary power to thedriving output terminals 1521 and 1522 based on the detected result.When the driving signal is no longer being supplied or a logic levelthereof is insufficient, the auxiliary power module 2510 provides theauxiliary power to keep the LED module 630 continuously light.

In an exemplary embodiment of FIG. 14A, an energy storage unit of theauxiliary power module 2510 can be implemented by a supercapacitor(e.g., electric double-layer capacitor, EDLC). In such an embodiment,since the supercapacitor provides the filtering function which is thesame as the filtering circuit 520, the filtering circuit 520 can beremoved in this embodiment.

In another exemplary embodiment, the LED lighting module 530 or LEDmodule 630 can be driven merely by the auxiliary power provided by theauxiliary power module 2510, and the external driving signal is merelyused for charging the auxiliary power module 2510. Since such anembodiment applies the auxiliary power provided by the auxiliary powermodule 2510 as the only power source for the LED lighting module 530 orthe LED module 630, regardless of whether the external driving signal isprovided by commercial electricity or a ballast, the external drivingsignal charges the energy storage unit first, and then the energystorage unit is used for supplying power to the LED module. Accordingly,the LED tube lamp applying said power architecture may be compatiblewith the external driving signal provided by commercial electricity or aballast.

From the perspective of the structure, since the auxiliary power module2510 is connected between the outputs of the filtering circuit 520(i.e., the first filtering output 521 and the second filtering output522) or the outputs of the driving circuit 1530 (i.e., the first drivingoutput terminal 1521 and the second driving output terminal 1522), thecircuit components of the auxiliary power module 2510 can be placed, inan exemplary embodiment, in the lamp tube (e.g., the position adjacentto the LED lighting module 530 or LED module 630 and between the two endcaps), such that the power transmission loss caused by the long wiringcan be avoided. In another exemplary embodiment, the circuit componentsof the auxiliary power can be placed in at least one of the end caps,such that the heat generated by the auxiliary power module 2510 whencharging and discharging does not affect operation and illumination ofthe LED module.

FIG. 14C is a schematic diagram of an auxiliary power module accordingto an embodiment. The auxiliary power module 2610 can be applied, forexample, to the configuration of the auxiliary power module 2510illustrated in FIG. 14B. The auxiliary power module 2610 comprises anenergy storage unit 2613 and a voltage detection circuit 2614. Theauxiliary power module further comprises an auxiliary power positiveterminal 2611 and an auxiliary power negative terminal 2612 for beingrespectively coupled to the filtering output terminals 521 and 522 orthe driving output terminals 1521 and 1522. The voltage detectioncircuit 2614 detects a logic level of a signal at the auxiliary powerpositive terminal 2611 and the auxiliary power negative terminal 2612 todetermine whether releasing outward the power of the energy storage unit2613 through the auxiliary power positive terminal 2611 and theauxiliary power negative terminal 2612.

In some embodiments, the energy storage unit 2613 is a battery or asupercapacitor. When a voltage difference of the auxiliary powerpositive terminal 2611 and the auxiliary power negative terminal 2612(the drive voltage for the LED module) is higher than the auxiliarypower voltage of the energy storage unit 2613, the voltage detectioncircuit 2614 charges the energy storage unit 2613 by the signal in theauxiliary power positive terminal 2611 and the auxiliary power negativeterminal 2612. When the drive voltage is lower than the auxiliary powervoltage, the energy storage unit 2613 releases the stored energy outwardthrough the auxiliary power positive terminal 2611 and the auxiliarypower negative terminal 2612.

The voltage detection circuit 2614 comprises a diode 2615, a bipolarjunction transistor (BJT) 2616 and a resistor 2617. A positive end ofthe diode 2615 is coupled to a positive end of the energy storage unit2613 and a negative end of the diode 2615 is coupled to the auxiliarypower positive terminal 2611. The negative end of the energy storageunit 2613 is coupled to the auxiliary power negative terminal 2612. Acollector of the BJT 2616 is coupled to the auxiliary power positiveterminal 2611, and an emitter thereof is coupled to the positive end ofthe energy storage unit 2613. One end of the resistor 2617 is coupled tothe auxiliary power positive terminal 2611 and the other end is coupledto a base of the BJT 2616. When the collector of the BJT 2616 is acut-in voltage higher than the emitter thereof, the resistor 2617conducts the BJT 2616. When the power source provides power to the LEDtube lamp normally, the energy storage unit 2613 is charged by thefiltered signal through the filtering output terminals 521 and 522 andthe conducted BJT 2616 or by the driving signal through the drivingoutput terminals 1521 and 1522 and the conducted BJT 2616 until that thecollector-emitter voltage of the BJT 2616 is lower than or equal to thecut-in voltage. When the filtered signal or the driving signal is nolonger being supplied or the logic level thereof is insufficient, theenergy storage unit 2613 provides power through the diode 2615 to keepthe LED lighting module 530 or the LED module 630 continuously light.

In some embodiments, the maximum voltage of the charged energy storageunit 2613 is at least one cut-in voltage of the BJT 2616 lower than thevoltage difference applied between the auxiliary power positive terminal2611 and the auxiliary power negative terminal 2612. The voltagedifference provided between the auxiliary power positive terminal 2611and the auxiliary power negative terminal 2612 is a turn-on voltage ofthe diode 2615 lower than the voltage of the energy storage unit 2613.Hence, when the auxiliary power module 2610 provides power, the voltageapplied at the LED module 630 is lower (about the sum of the cut-involtage of the BJT 2616 and the turn-on voltage of the diode 2615). Inthe embodiment shown in the FIG. 14B, the brightness of the LED module630 is reduced when the auxiliary power module supplies power thereto.Thereby, when the auxiliary power module is applied to an emergencylighting system or a constant lighting system, the user realizes themain power supply, such as commercial power, is abnormal and thenperforms necessary precautions therefor.

In addition to utilizing the embodiments illustrated in FIG. 14A to FIG.14C in a single tube lamp architecture for emergency power supply, theembodiments also can be utilized in a lamp module including a multi tubelamp. Taking the lamp module having four parallel arranged LED tubelamps as an example, in an exemplary embodiment, one of the LED tubelamps includes the auxiliary power module. When the external drivingsignal is abnormal, the LED tube lamp including the auxiliary powermodule is continuously lighted up and the others LED tube lamps go off.According to the consideration of the uniformity of illumination, theLED tube lamp having the auxiliary power module can be arranged in themiddle position of the lamp module.

In another exemplary embodiment, a plurality of the LED tube lampsrespectively include the auxiliary power module. When the externaldriving signal is abnormal, the LED tube lamps including the auxiliarypower module are continuously lighted up and the other LED tube lamps(if any) go off. In this way, even if the lamp module is operated in anemergency situation, a certain brightness can still be provided for thelamp module. In addition, if there are two LED lamps that have theauxiliary power module, the LED tube lamps having the auxiliary powermodule can be arranged, according to the consideration of the uniformityof illumination, in a staggered way with the LED tube lamps that don'thave the auxiliary power module.

In still another exemplary embodiment, a plurality of the LED tube lampsrespectively include the auxiliary power module. When the externaldriving signal is abnormal, part of the LED tube lamps including theauxiliary power module is first lighted up by the auxiliary power, andthe other part of the LED tube lamps including the auxiliary powermodule is then lighted up by the auxiliary power after a predeterminedperiod. In this way, the lighting time of the lamp module can beextended during the emergency situation by coordinating the auxiliarypower supply sequence of the LED tube lamps.

The embodiment of coordinating the auxiliary power supply sequence ofthe LED tube lamps can be implemented by setting different start-up timefor the auxiliary power module disposed in different tube lamp, or bydisposing controllers in each tube lamp for communicating the operationstate of each auxiliary power module. The present invention is notlimited thereto.

FIG. 14D is a block diagram of a power supply module in an LED tube lampaccording to an exemplary embodiment. Referring to FIG. 14D, the LEDtube lamp of the present embodiment includes a rectifying circuit 510, afiltering circuit 520, an LED lighting module 530, and an auxiliarypower module 2710. The LED lighting module 530 of the present embodimentcan only include the LED module or include the driving circuit and theLED module, the present invention is not limited thereto. Compared tothe embodiment of FIG. 14B, the auxiliary power module 2710 of thepresent embodiment is connected between the pins 501 and 502 to receivethe external driving signal and perform a charge-discharge operationbased on the external driving signal.

In some embodiments, the operation of the auxiliary power module 2710can be similar to an Off-line uninterruptible power supply (Off-lineUPS). Specifically, when an AC power source (e.g., the mainselectricity, the commercial electricity or the power grid) normallysupplies the external driving signal to the LED tube lamp, the externaldriving signal is supplied to the rectifying circuit 510 while chargingthe auxiliary power module 2710. Once the AC power source is unstable orabnormal, the auxiliary power module 2710 takes the place of the ACpower source to supply power to the rectifying circuit 510 until the ACpower source recovers normal power supply. Therefore, the auxiliarypower module 2710 can operate in a backup manner, wherein the auxiliarypower module 2710 intervenes the power supply process only when the ACpower source is unstable or abnormal. Herein, the power supplied by theauxiliary power module 2710 can be an AC power or a DC power.

In some embodiments, the current path between the AC power source andthe rectifying circuit 510 is cut off when the AC power source isunstable or abnormal. For example, the unstable AC power source refersto at least one of the voltage variation, the current variation, and thefrequency variation of the external driving signal exceed a threshold.The abnormal AC power source refers to at least one of the voltage, thecurrent, and the frequency of the external driving signal being lower orhigher than a normal operation range.

The auxiliary power module 2710 includes an energy storage unit and avoltage detection circuit. The voltage detection circuit detects theexternal driving signal, and determines whether the energy storageprovides the auxiliary power to the input terminal of the rectifyingcircuit 510 according to the detection result. When the external drivingsignal stops providing or the AC signal level of the external drivingsignal is insufficient, the energy storage unit of the auxiliary powermodule 2710 provides the auxiliary power, such that the LED lightingmodule 530 continues to emit light based on the auxiliary power providedby the auxiliary power module 2710. In the practical application, theenergy storage unit for providing auxiliary power can be implemented byan energy storage assembly such as a battery or a supercapacitor,however, the present invention is not limited thereto.

FIG. 14E illustrates an exemplary configuration of the auxiliary powermodule 2710 operating in an Off-line UPS mode according to someembodiments of the present invention. Referring to FIG. 14E, theauxiliary power module 2710 includes a charging unit 2712 and anauxiliary power supply unit 2714. The charging unit 2712 has an inputterminal coupled to an external AC power source EP and an outputterminal coupled to an input terminal of the auxiliary power supply unit2714. The auxiliary power supply unit 2714 has the input terminalcoupled to the output terminal of the charging unit 2712 and an outputterminal coupled to a power loop between the external AC power source EPand the rectifying circuit 510. Specifically, when the external AC powersource EP operates normally, the power, supplied by the external ACpower source EP, will be provided to the input terminal of therectifying circuit 510 as an external driving signal Sed. In themeantime, the charging unit 2712 charges the auxiliary power supply unit2714 based on the power supplied by the external AC power source EP, andthe auxiliary power supply unit 2714 does not output power to therectifying circuit 510 in response to the external driving signal Sedthat is correctly transmitted on the power loop. When the external ACpower source EP is unstable or abnormal, the auxiliary power supply unit2714 starts to supply an auxiliary power, served as the external drivingsignal Sed, to the rectifying circuit 510.

FIG. 14F is a block diagram of a power supply module in an LED tube lampaccording to an exemplary embodiment. Referring to FIG. 14F, the LEDtube lamp of the present embodiment includes a rectifying circuit 510, afiltering circuit 520, a LED lighting module 530 and an auxiliary powermodule 2710′. Compared to the embodiment illustrated in FIG. 14D, theinput terminals Pi1 and Pi2 of the auxiliary power module 2710′ areconfigured to receive an external driving signal and perform acharge-discharge operation based on the external driving signal, andthen supply an auxiliary power, generated from the output terminals Po1and Po2, to the rectifying circuit 510. From the perspective of thestructure of the LED tube lamp, the input terminals Pi1 and Pi2 or theoutput terminals Po1 and Po2 of the auxiliary power module 2710′ areconnected to the pins of the LED tube lamp (e.g., 501 and 502 in FIG.14A or 14B). If the pins 501 and 502 of the LED tube lamp are connectedto the input terminals Pi1 and Pi2 of the auxiliary power module 2710′,it means the auxiliary power module 2710′ is disposed inside the LEDtube lamp and receives the external driving signal through the pins 501and 502. On the other hand, if the pins 501 and 502 of the LED tube lampare connected to the output terminals Po1 and Po2 of the auxiliary powermodule 2710′, it means the auxiliary power module 2710′ is disposedoutside the LED tube lamp and outputs the auxiliary power to therectifying circuit through the pins 501 and 502. The detail structure ofthe auxiliary power module will be further described in the followingembodiments.

In some embodiments, the operation of the auxiliary power module 2710′can be similar to an On-line uninterruptible power supply (On-line UPS).Under the On-line UPS operation, the external AC power source would notdirectly supply power to the rectifying circuit 510, but supplies powerthrough the auxiliary power module 2710′. Therefore, the external ACpower source can be isolated from the LED tube lamp, and the auxiliarypower module 2710′ intervenes the whole power supply process, so thatthe power supplied to the rectifying circuit 510 is not affected by theunstable or abnormal AC power source.

FIG. 14G illustrates an exemplary configuration of the auxiliary powermodule 2710′ operating in an On-line UPS mode according to someembodiments of the present invention. Referring to FIG. 14G, theauxiliary power module 2710′ includes a charging unit 2712′ and anauxiliary power supply unit 2714′. The charging unit 2712′ has an inputterminal coupled to an external AC power source EP and an outputterminal coupled to a first input terminal of the auxiliary power supplyunit 2714′. The auxiliary power supply unit 2714′ further has a secondinput terminal coupled to the external AC power source EP and an outputterminal coupled to the rectifying circuit 510. Specifically, when theexternal AC power source EP operates normally, the auxiliary powersupply unit 2714′ performs the power conversion based on the powersupplied by the external AC power source EP, and accordingly provides anexternal driving signal Sed to the rectifying circuit 510. In themeantime, the charging unit 2712′ charges an energy storage unit of theauxiliary power supply unit 2714′. When the external AC power source isunstable or abnormal, the auxiliary power supply unit 2714′ performs thepower conversion based on the power stored in the energy storage unit,and accordingly provides the external driving signal Sed to therectifying circuit 510. It should be noted that the power conversiondescribed herein could be rectification, filtering, boost-conversion,buck-conversion or a reasonable combination of above operations. Thepresent invention is not limited thereto.

In some embodiments, the operation of the auxiliary power module 2710′can be similar to a Line-Interactive UPS. The basic operation of theauxiliary power module 2710′ under a Linear-Interactive UPS mode issimilar to the auxiliary power module 2710 under the Off-line UPS mode,the difference between the Line-Interactive UPS mode and the Off-lineUPS mode is the auxiliary 2710′ has a boost and buck compensationcircuit and can monitor the power supply condition of the external ACpower source at any time. Therefore, the auxiliary power module 2710′can correct the power output to the power supply module of the LED tubelamp when the external AC power source is not ideal (e.g., the externaldriving signal is unstable but the variation does not exceed thethreshold value), so as to reduce the frequency of using the battery forpower supply.

FIG. 14H illustrates an exemplary configuration of the auxiliary powermodule 2710′ operating in the Line-Interactive mode according to someembodiments of the present invention. Referring to FIG. 14H, theauxiliary power module 2710′ includes a charging unit 2712′, anauxiliary power supply unit 2714′ and a switching unit 2716′. Thecharging unit 2712′ has an input terminal coupled to an external ACpower source EP. The switching unit 2716′ is coupled between an outputterminal of the auxiliary power supply unit 2714′ and an input terminalof the rectifying circuit 510, in which the switching unit 2716′ mayselectively conduct a current on a path between the external AC powersource EP and the rectifying circuit 510 or on a path between theauxiliary power supply unit 2714′ and the rectifying circuit 510according to the power supply conduction of the external AC power sourceEP. In detail, when the external AC power source is normal, theswitching unit 2716′ is switched to conduct a current on the pathbetween the external AC power source EP and the rectifying circuit 510and cut off the path between the auxiliary power supply unit 2714′ andthe rectifying circuit 510. Thus, when the external AC power source isnormal, the external AC power source EP provides power, regarded as theexternal driving signal Sed, to the input terminal of the rectifyingcircuit 510 via the switching unit 2716′. In the meantime, the chargingunit 2712′ charges the auxiliary power unit 2714′ based on the externalAC power source EP. When the external AC power source is unstable orabnormal, the switching unit 2716′ is switched to conduct a current onthe path between the auxiliary power supply unit 2714′ and therectifying circuit 510 and cut off the path between the AC power sourceEP and the rectifying circuit 510. The auxiliary power supply unit 2714′starts to supply power, regarded as the external driving signal Sed, tothe rectifying circuit 510.

In the embodiments of the auxiliary power module, the auxiliary powerprovided by the auxiliary power supply unit 2714/2714′ can be in eitherAC or DC. When the auxiliary power is provided in AC, the auxiliarypower supply unit 2714/2714′ includes, for example, an energy storageunit and a DC-to-AC converter. When the auxiliary power is provided inDC, the auxiliary power supply unit 2714/2714′ includes, for example, anenergy storage unit and a DC-to-DC converter, or simply includes anenergy storage unit; the present invention is not limited thereto. Theenergy storage unit can be a set of batteries. The DC-to-DC convertercan be a boost converter, a buck converter or a buck-boost converter.

In an exemplary embodiment, the brightness of the LED module on theexternal driving signal is different from the brightness of the LEDmodule on the auxiliary power. Therefore, a user may find the externalpower is abnormal when observing that the brightness of LED modulechanged, and thus the user can eliminate the problem as soon aspossible. In this manner, the operation of the auxiliary power module2710 can be considered as an indication for indicating whether theexternal driving signal is normally provided, by providing the auxiliarypower having the output power different from the external driving signalwhen the external driving signal is abnormal. For example, in someembodiments, the luminance of the LED module is 1600 to 2000 lm whenbeing lighted up by the external driving signal; and the luminance ofthe LED module is 200 to 250 lm when being lighted up by the auxiliarypower. From the perspective of the auxiliary power module 2710, in orderto let the luminance of the LED module reach 200-250 lm, the outputpower of the auxiliary power module 2710 is, for example, 1 watt to 5watts, but the present invention is not limited thereto. In addition,the electrical capacity of the energy storage unit in the auxiliarypower module 2710 may be, for example, 1.5 to 7.5 Wh (watt-hour) orabove, so that the LED module can be lighted up for 90 minutes under200-250 lm based on the auxiliary power. However, the present inventionis not limited thereto.

From the perspective of the structure, FIG. 14I illustrates a schematicstructure of an auxiliary power module disposed in an LED tube lampaccording to an exemplary embodiment. In the present embodiment, inaddition, or as an alternative, to disposing the auxiliary power module2710/2710′ in the lamp tube 1 as the embodiment mentioned above, theauxiliary power module 2710/2170′ can be disposed in the end cap 3 aswell. In order to make the description more clear, the auxiliary powermodule 2710 is chosen as a representative of the auxiliary power modules2710 and 2710′ in the following paragraph, and only 2710 is marked onthe figures. When the auxiliary power module 2710 is disposed in the endcap 3, the auxiliary power module 2710 connects to the correspondingpins 501 and 502 via internal wiring of the end cap 3, so as to receivethe external driving signal provided to the pins 501 and 502. Comparedto the structure of disposing the auxiliary power module into the lamptube 1, the auxiliary power module 2710 can be disposed far apart fromthe LED module since the auxiliary power module 2710 is disposed in theend cap 3 which is connected to the respective end of the lamp tube 1.Therefore, the operation and illumination of the LED module won't beaffected by the charging or discharging heat generated by the auxiliarypower module 2710. In addition, the auxiliary power module 2710 and thepower supply module of the LED tube lamp can be disposed in the same endcap, or disposed in the different end caps on the respective ends of thelamp tube. In some embodiments, if the auxiliary power module 2710 andthe power supply module of the LED tube lamp are respectively disposedin the different end caps, each module may have more area for circuitlayout.

In another exemplary embodiment, the auxiliary power module 2710 can bedisposed in a lamp socket corresponding to the LED tube lamp as shown inFIG. 14J, which illustrates a schematic structure of an auxiliary powermodule disposed in a lamp socket according to an exemplary embodiment.The lamp socket 1_LH includes a base 101_LH and a connecting socket102_LH. The base 101_LH has power line disposed inside and is adapted tolock/attach to a fixed object such as a wall or a ceiling. Theconnecting socket 102_LH has slot corresponding to the pin (e.g., thepins 501 and 502) on the LED tube lamp, in which the slot iselectrically connected to the corresponding power line. In the presentembodiment, the connecting socket 102_LH and the base 101_LH can beformed in one piece, or the connecting socket 102_LH can be removablydisposed on the base 101_LH. The invention is not limited one of theseembodiments.

When the LED tube lamp is installed on the lamp socket 1_LH, the pins onboth end caps 3 are respectively inserted into the slot of thecorresponding connecting socket 102_LH, and thus the power line can beconnected to the LED tube lamp for providing the external driving signalto the corresponding pins of the LED tube lamp. Taking the configurationof the left end cap 3 as an example, when the pins 501 and 502 areinserted into the slots of the connecting socket 102_LH, the auxiliarypower module 2710 is electrically connected to the pins 501 and 502 viathe slots, so as to implement the connection configuration shown in FIG.14D.

Compared to the embodiment of disposing the auxiliary power module 2710in the end cap 3, the connecting socket 102_LH and the auxiliary powermodule 2710 can be integrated as a module since the connecting socketcan be designed as a removable configuration in an exemplary embodiment.Under such configuration, when the auxiliary power module 2710 has afault or the service life of the energy storage unit in the auxiliarypower module 2710 has run out, a new auxiliary power module can bereplaced for use by replacing the modularized connecting socket 102_LH,instead of replacing the entire LED tube lamp. Thus, in addition toreducing the thermal effect of the auxiliary power module, themodularized design of the auxiliary power module makes the replacementof the auxiliary power module easier. Therefore, the durability of theLED tube lamp is improved since it is no longer necessary to replace theentire LED tube lamp when a problem occurs to the auxiliary powermodule. In addition, in some embodiments, the auxiliary power module2710 can be disposed inside the base 101_LH or outside the base 101_LH,the present invention is not limited thereto.

In summary, the structural configuration of the auxiliary power module2710 can be divided into the following two types: (1) the auxiliarypower module is integrated into the LED tube lamp; and (2) the auxiliarypower module 2710 is disposed independent from the LED tube lamp. Underthe configuration of disposing the auxiliary power module 2710independent from the LED tube lamp, if the auxiliary power module 2710operates in the Off-line UPS mode, the auxiliary power module 2710 andthe external AC power source can provide power, through different pinsor through sharing at least one pin, to the LED tube lamp. On the otherhand, if the auxiliary power module 2710 operates in the On-line UPSmode or the Line-Interactive mode, the external AC power source providespower through the auxiliary power module 2710 rather than directly tothe pins of the LED tube lamp. The detailed configuration of disposingthe auxiliary power module independent from the LED tube lamp(hereinafter the independent auxiliary power module) is furtherdescribed below.

It should be noted that the combination of the lamp and the lamp socketcould be regarded as a light fixture, a lamp fixture, a light fitting orluminaries. For example, the lamp socket in the disclosure can beregarded as a part of the light fixture for securing, attaching orappending as to a house, apartment building, etc., and for holding andproviding power to the lamps. In addition, the connecting sockets 102_LHcan be described as tombstone sockets of the light fixture.

FIG. 14K is a block diagram of an LED lighting system according to anexemplary embodiment. Referring to FIG. 14K, the LED lighting systemincludes an LED tube lamp 500 and an auxiliary power module 2810. TheLED tube lamp 500 includes rectifying circuits 510 and 540, a filteringcircuit 520 and an LED lighting module 530. The LED lighting module 530includes a driving circuit (optional) and an LED module. The rectifyingcircuits 510 and 540 can be respectively implemented by the full-waverectifier 610 illustrated in FIG. 9A or the half-wave rectifier 710 asshown in FIG. 9B, in which two input terminals of the rectifying circuit510 are coupled to the pins 501 and 502 and two input terminals of therectifying circuit 540 are coupled to the pins 503 and 504.

In present embodiment, the LED tube lamp 500 is configured as a dual-endpower supply structure for example. The external AC power source EP iscoupled to the pins 501 and 502 on the respective end caps of the LEDtube lamp 500, and the auxiliary power module 2810 is coupled to thepins 503 and 504 on the respective end caps of the LED tube lamp 500. Inthis embodiment, the external AC power source EP and the auxiliary powermodule 2810 provide power to the LED tube lamp 500 through differentpairs of the pins. Although the present embodiment is illustrated indual-end power supply structure for example, the present invention isnot limited thereto. In another embodiment, the external AC power sourceEP can provide power through the pins 501 and 503 on the end cap at oneside of the lamp tube (i.e., the single-end power supply structure), andthe auxiliary power module 2810 can provide power through the pins 502and 504 on the end cap at the other side of the lamp tube. Accordingly,no matter whether the LED tube lamp 500 is configured in the single-endor the dual-end power supply structure, the unused pins of the originalLED tube lamp (e.g., 503 and 504 illustrated in FIG. 14K) can be theinterface for receiving the auxiliary power, so that the emergencylighting function can be integrated in the LED tube lamp 500.

FIG. 14L is a block diagram of an LED lighting system according toanother exemplary embodiment. Referring to FIG. 14L, the LED lightingsystem includes an LED tube lamp 500′ and an auxiliary power module2910. The LED tube lamp 500′ includes a rectifying circuit 510′, afiltering circuit 520 and an LED lighting module 530. The LED lightingmodule 530 includes a driving circuit (optional) and an LED module. Therectifying circuit 510′ can be implemented by the rectifying circuit 910having three bridge arms as shown in FIGS. 9D to 9F, in which therectifying circuit 510′ has a first signal input terminal P1 coupled tothe pin 501, a second signal input terminal P2 coupled to the pin 502and the auxiliary power module 2910 and a third input terminal P3coupled to the auxiliary power module 2910.

In the present embodiment, the LED tube lamp 500′ is configured as adual-end power supply structure for example. The external AC powersource EP is coupled to the pins 501 and 502 on the respective end capsof the LED tube lamp 500. The difference between the present embodimentand the embodiment illustrated in FIG. 14K is that besides being coupledto the pin 503, the auxiliary power module 2910 further shares the pin502 with the external AC power source EP. Under the configuration ofFIG. 14L, the external AC power source EP provides power to the signalinput terminals P1 and P2 of the rectifying circuit 510′ though the pins501 and 502, and the auxiliary power module 2910 provides power to thesignal input terminals P2 and P3 of the rectifying circuit 510′ throughthe pins 502 and 503. In detail, if the leads connected to the pins 501and 502 are respectively configured as a live wire (denoted by “(L)”)and a neutral wire (denoted by “(N)”), the auxiliary power module 2910shares the lead (N) with the external AC power source EP and has a leadfor transmitting power as a live wire distinct from the external ACpower source EP.

From the perspective of operation, when the external AC power sourcenormally operates, the rectifying circuit 510′ performs the full-waverectification by the bridge arms corresponding to the signal inputterminals P1 and P2, so as to provide power to the LED lighting module530 based on the external AC power source EP. When the external AC powersource is unstable or abnormal, the rectifying circuit 510′ performs thefull-wave rectification by the bridge arms corresponding to the signalinput terminals P2 and P3, so as to provide power to the LED lightingmodule based on the auxiliary power provided by the auxiliary powermodule 2910.

In addition, since the LED tube lamp receives the auxiliary powerprovided by the auxiliary power module 2910 through sharing the pin 502,an unused pin 504 can be used as a signal input interface of othercontrol functions. Said other control functions can be at least one of adimming function, a communication function and a sensing function,though the present invention is not limited thereto. The embodiment ofintegrating the dimming function through the unused pin 504 is furtherdescribed below.

FIG. 14M is a block diagram of an LED lighting system according to stillanother exemplary embodiment. Referring to FIG. 14M, the LED lightingsystem includes an LED tube lamp 500′ and an auxiliary power module2910. The LED tube lamp 500′ includes a rectifying circuit 510′, afiltering circuit 520, a driving circuit 1530 and an LED module 630. Theconfiguration of the present embodiment is similar to the embodimentillustrated in FIG. 14L. The difference between the embodiments of FIGS.14M and 14L is, as shown in FIG. 14M, the pin 504 of the LED tube lamp500′ is further coupled to a dimming control circuit 550, in which thedimming control circuit 550 is coupled to the driving circuit 1530through the pin 504, so that the driving circuit 1530 can adjust themagnitude of the driving current, supplied to the LED module 630,according to a dimming signal received from the dimming control circuit550. Therefore, the brightness and/or the color temperature of the LEDmodule 630 can be varied according to the dimming signal.

For example, the dimming control circuit 550 can be implemented by acircuit including a variable impedance component (e.g., a variableresistor, a variable capacitor or a variable inductor) and a signalconversion circuit. The impedance of the variable impedance componentcan be tuned by a user, so that the dimming control circuit 550generates the dimming signal having signal level corresponding to theimpedance. After converting the signal formation (e.g., signal level,frequency or phase) of the dimming signal to conform the signalformation of the driving circuit 1530, the converted dimming signal istransmitted to the driving circuit 1530, so that the driving circuit1530 adjusts the magnitude of the driving current based on the converteddimming signal. In some embodiments, the brightness of the LED module630 can be adjusted by tuning the frequency or the reference level ofthe driving signal. In some embodiments, the color temperature of theLED module 630 can be adjusted by tuning the brightness of the red LEDunits.

It should be noted that, by utilizing the structural configurations asshown in FIGS. 14I and 14J, the auxiliary power module 2810/2910 canobtain the similar benefits and advantages described in the embodimentsof FIGS. 14I and 14J. In addition, although the dummy pins (i.e., thepins not for receiving the external driving signal, such as the pins 503and 504) illustrated in FIGS. 11K to 11M are used for receiving theauxiliary power and the dimming signal, the invention is not limitedthereto. In some embodiments, the dummy pins can be used for otherfunctions, such as receiving a remote control signal or outputting asensing signal, by correspondingly disposing circuits connected to thedummy pins for performing the functions. For example, the dummy pins inthe LED tube lamp can be configured to a signal input/output interfacefor performing certain functions.

Under a lamp module architecture having multi tube lamps, which issimilar with the embodiments described in FIG. 14A to FIG. 14N, theauxiliary power module can be disposed in one tube lamp, or in pluraltube lamps, in which the multi tube lamps architectures based on theconsideration of the uniformity of illumination are adapted to thepresent embodiment as well. The difference between the embodiment havingmulti tube lamps and the embodiments illustrated in FIG. 14A to FIG. 14Nis that the auxiliary power module disposed in one of the tube lamps maysupply power to the other tube lamps.

It should be noted that, although the description of the lamp modulehaving multi tube lamps herein is taking the four parallel LED tubelamps as an example, those skilled in the art should understand, basedon the description mentioned above, how to implement an auxiliary powersupply by selecting and disposing the suitable energy storage unit.Therefore, any embodiments illustrated in which the auxiliary powermodule 2710 provides auxiliary power to one or plural tube lamps, suchthat the corresponding LED tube lamp has a specific illuminance inresponse to the auxiliary power, may be implemented according to thedisclosed embodiments.

In another exemplary embodiment, the auxiliary power modules 2510, 2610,2710, 2810 and 2910 determine whether to provide the auxiliary power tothe LED tube lamp according to a lighting signal. Specifically, thelighting signal is an indication signal indicating the switching stateof the lamp switch. For example, the signal level of the lighting signalcan be adjusted to a first level (e.g., high logic level) or a secondlevel different from the first level (e.g., low logic level) accordingto the switching of the lamp switch. When a user toggles the lamp switchto an on-position, the lighting signal is adjusted to the first level;and when the user toggles the lamp switch to an off-position, thelighting signal is adjusted to the second level. For example, the lampswitch may be switched to the on-position when the lighting signal is atthe first level and to the off-position when the lighting signal is atthe second level. The generation of the lighting signal can beimplemented by a circuit capable of detecting the switching state of thelamp switch.

In still another exemplary embodiment, the auxiliary power module2510/2610/2710/2810/2910 further includes a lighting determinationcircuit for receiving the lighting signal and determining whether theenergy storage unit provides the auxiliary power to the end of the LEDtube lamp (e.g., to provide the auxiliary power to the LED module)according to the signal level of the lighting signal and the detectionresult of the voltage detection circuit. Specifically, based on thesignal level of the lighting signal and the detection result, there arethree different states as follows: (1) the lighting signal is at thefirst level and the external driving signal is normally provided; (2)the lighting signal is at the first level and the external drivingsignal stops being provided or the AC signal level of the externaldriving signal is insufficient; and (3) the lighting signal is at thesecond level and the external driving signal stops being provided.Herein, state (1) is the situation where a user turns on the lamp switchand the external driving signal is normally provided, state (2) is thesituation where a user turns on the lamp switch however a problem occursto the external power supply, and state (3) is the situation where auser turns off the lamp switch so that the external power supply isstopped.

In the present exemplary embodiment, states (1) and (3) belong to normalstates, which means the external power is normally provided or stops inaccordance with the user's control. Therefore, under states (1) and (3),the auxiliary power module does not provide auxiliary power to the endof the LED tube lamp (e.g., to the LED module). More specifically, thelighting determination circuit controls the energy storage unit not toprovide the auxiliary power to the end of the LED tube lamp according tothe determination result of states (1) and (3). In state (1), theexternal driving signal is directly input to the rectifying circuit 510and charges the energy storage unit. In state (3), the external drivingsignal stops being provided so that the energy unit is not charged bythe external driving signal.

State (2) represents the external power is not provided to the tube lampwhen the user turns on the light, therefore, the lighting determinationcircuit controls the energy storage unit to provide the auxiliary powerto the rear end according to the determination result indicating state(2), so that the LED lighting module 530 emits light based on theauxiliary power provided by the energy storage unit.

Accordingly, based on the application of the lighting determinationcircuit, the LED lighting module 530 may have three different luminancevariations. The LED lighting module 530 has a first luminance (e.g.,1600 to 2200 lm) when the external power is normally supplied; thelighting module 530 has a second luminance (e.g., 200 to 250 lm) whenthe external power is abnormal and the power supply is changed to theauxiliary power; and the lighting module 530 has a third luminance(e.g., does not light up the LED module) when the user turns off thepower on their own such that the external power is not provided to theLED tube lamp.

More specifically, in accordance with the embodiment of FIG. 14C, thelighting determination circuit is, for example, a switch circuit (notshown) connected between the auxiliary power positive terminal 2611 andthe auxiliary power negative terminal 2612 in series. The controlterminal of the switch circuit receives the lighting signal. When thelighting signal is at the first level, the switch circuit is conductedin response to the lighting signal, such that the external drivingsignal charges the energy storage unit 2613 via the auxiliary powerpositive terminal 2611 and the auxiliary power negative terminal 2612when the external driving signal is normally supplied (state (1)), ormakes the energy storage unit 2613 discharge to the LED lighting module530 or LED module 630 via the auxiliary power positive terminal 2611 andthe auxiliary power negative terminal 2612 when the external drivingsignal stops providing or the AC signal level of the external drivingsignal is insufficient (state (2)). On the other hand, when the lightingsignal is at the second level, the switch circuit is cut off in responseto the lighting signal (state (3)). At this time, even though theexternal driving signal stops being provided or the AC signal level isinsufficient, the energy storage unit 2613 won't provide the auxiliarypower to the rear end.

Referring to FIG. 15A, a block diagram of an LED tube lamp including apower supply module in accordance with certain embodiments isillustrated. Compared to the LED lamp shown in FIG. 8D, the LED tubelamp of FIG. 15A includes a rectifying circuit 510, a filtering circuit520, and an LED lighting module 530, and further includes aninstallation detection module 2520 (also known as an electric shockprotection module). The installation detection module 2520 is coupled tothe rectifying circuit 510 via an installation detection terminal 2521and is coupled to the filtering circuit 520 via an installationdetection terminal 2522. The installation detection module 2520 detectsthe signal passing through the installation detection terminals 2521 and2522 and determines whether to cut off an LED driving signal (e.g., anexternal driving signal) passing through the LED tube lamp based on thedetected result. The installation detection module 2520 includescircuitry configured to perform the steps of detecting the signalpassing through the installation detection terminals 2521 and 2522 anddetermining whether to cut off an LED driving signal, and thus may bereferred to as an installation detection circuit, or more generally as adetection circuit or cut-off circuit. When an LED tube lamp is not yetinstalled on a lamp socket or holder, or in some cases if it is notinstalled properly or is only partly installed (e.g., one side isconnected to a lamp socket, but not the other side yet), theinstallation detection module 2520 detects a smaller current compared toa predetermined current (or current value) and determines the signal ispassing through a high impedance through the installation detectionterminals 2521 and 2522. In this case, in certain embodiments, theinstallation detection circuit 2520 is in a cut-off state to make theLED tube lamp stop working or limit the current flowing through thepower loop to less than 5 MIU, which can be referred to 5 mA at acertain frequency and is the requirement, defined in the safetycertification standard such as UL, of the Type-B LED tube lamp. The unitof “MIU” is defined by American National Standards Institute (ANSI)C101-1992. Otherwise, the installation detection module 2520 determinesthat the LED tube lamp has already been installed on the lamp socket orholder (e.g., when the installation detection module 2520 detects acurrent equal to or larger than a predetermined current and determinesthe signal is passing through a low impedance through the installationdetection terminals 2521 and 2522), and maintains conductingstate/current limiting state to make the LED tube lamp working normally.

For example, in some embodiments, when a current passing through theinstallation detection terminals 2521 and 2522 is greater than or equalto a specific, defined installation current (or a current value), whichmay indicate that the current supplied to the LED lighting module 530 isgreater than or equal to a specific, defined operating current, theinstallation detection module 2520 conducts current to make the LED tubelamp operate in a conducting state. For example, a current greater thanor equal to the specific current value may indicate that the LED tubelamp has correctly been installed in the lamp socket or holder. When thecurrent passing through the installation detection terminals 2521 and2522 is smaller than the specific, defined installation current (or thecurrent value), which may indicate that the current supplied to the LEDlighting module 530 is less than a specific, defined operating current,the installation detection module 2520 cuts off current to make the LEDtube lamp enter in a non-conducting state based on determining that theLED tube lamp has been not installed in, or does not properly connectto, the lamp socket or holder. In certain embodiments, the installationdetection module 2520 determines conducting or cutting off based on theimpedance detection to make the LED tube lamp operate in a conductingstate or enter non-conducting state. The LED tube lamp operating in aconducting state may refer to the LED tube lamp including a sufficientcurrent passing through the LED module to cause the LED light sources toemit light. The LED tube lamp operating in a cut-off state may refer tothe LED tube lamp including an insufficient current or no currentpassing through the LED module so that the LED light sources do not emitlight. Accordingly, the occurrence of electric shock caused by touchingthe conductive part of the LED tube lamp which is incorrectly installedon the lamp socket or holder can be efficiently avoided.

Compared with a general LED power supply module, since the power supplymodule provided with the installation detection module 2520 has theeffect of preventing electric shock, there is no need to dispose asafety capacitor (i.e., X capacitor) between the input terminals of therectifying circuit 510 (i.e., between the live wire (L) and the neutralwire (N)). From the perspective of the equivalent circuit of the powersupply module, having no X capacitor disposed between the inputterminals of the rectifying circuit 510 means the effective capacitancebetween the input terminals of the rectifying circuit 510 is, forexample, smaller than 47 nF. In the present embodiment, the power looprefers to the current path in the LED tube lamp, for example, the pathformed between the pins on the respective end caps.

More precisely, when an external AC power source is applied to the LEDtube lamp 500, the current flows from the pin on one end cap (e.g., leftend cap) to the pin on the other end cap (e.g., right end cap) andpasses through the leads and the components serially connected to thefirst terminal of the LED module (e.g., the positive terminal), the LEDmodule, the leads and the components serially connected to the secondterminal of the LED module (e.g., the negative terminal) in sequence.The pins, the leads, the components, and the LED module that the currentpasses through form the power loop.

It should be noted that, the issue of electric shock is raised since thepower loop is formed between the respective ends of the LED tube lampunder the dual-end power supply structure.

Referring to FIG. 15B, a block diagram of an installation detectionmodule in accordance with certain embodiments is illustrated. Theinstallation detection module includes a switch circuit 2580, adetection pulse generating module 2540, a detection result latchingcircuit 2560, and a detection determining circuit 2570. Certain of thesecircuits or modules may be referred to as first, second, third, etc.,circuits as a naming convention to differentiate them from each other.

The detection determining circuit 2570 is coupled to and detects thesignal between the installation detection terminals 2521 (through aswitch circuit coupling terminal 2581 and the switch circuit 2580) and2522. The detection determining circuit 2570 is also coupled to thedetection result latching circuit 2560 via a detection result terminal2571 to transmit the detection result signal to the detection resultlatching circuit 2560. The detection determining circuit 2570 may beconfigured to detect a current passing through terminals 2521 and 2522(e.g., to detect whether the current is above or below a specificcurrent value).

The detection pulse generating module 2540 is coupled to the detectionresult latching circuit 2560 via a pulse signal output terminal 2541,and generates a pulse signal to inform the detection result latchingcircuit 2560 of a time point for latching (storing) the detectionresult. For example, the detection pulse generating module 2540 may be acircuit configured to generate a signal that causes a latching circuit,such as the detection result latching circuit 2560 to enter and remainin a state that corresponds to one of a conducting state or a cut-offstate for the LED tube lamp. The detection result latching circuit 2560stores the detection result according to the detection result signal (ordetection result signal and pulse signal), and transmits or provides thedetection result to the switch circuit 2580 coupled to the detectionresult latching circuit 2560 via a detection result latching terminal2561. The switch circuit 2580 controls the state between conducting orcut off between the installation detection terminals 2521 and 2522according to the detection result.

In some embodiments, the detection pulse generating module 2540 may bereferred to as a first circuit 2540, the detection result latchingcircuit 2560 may be referred to as a second circuit 2560, the switchcircuit 2580 may be referred to as a third circuit 2580, the detectiondetermining circuit 2570 may be referred to as a fourth circuit 2570,the switch circuit coupling terminal 2581 may be referred to as a firstterminal 2581 and the detection result terminal 2571 may be referred toas a second terminal 2571, the pulse signal output terminal 2541 may bereferred to as a third terminal 2541, the detection result latchingterminal 2561 may be referred to as a fourth terminal 2561, theinstallation detection terminal 2521 may be referred to as a firstinstallation detection terminal 2521, and the installation detectionterminal 2522 may be referred to as a second installation detectionterminal 2522. In this exemplary embodiment, the fourth circuit 2570 iscoupled to the third circuit 2580 and the second circuit 2560 via thefirst terminal 2581 and the second terminal 2571, respectively, thesecond circuit 2560 is also coupled to the first circuit 2540 and thethird circuit 2580 via the third terminal 2541 and the fourth terminal2561, respectively.

In some embodiments, the fourth circuit 2570 is configured for detectinga signal between the first installation detection terminal 2521 and thesecond installation detection terminal 2522 through the first terminal2581 and the third circuit 2580. For example, because of the aboveconfiguration, the fourth circuit 2570 is capable of detecting anddetermining whether a current passing through the first installationdetection terminal 2521 and the second installation detection terminal2522 is below or above a predetermined current value and transmitting orproviding a detection result signal to the second circuit 2560 via thesecond terminal 2571.

In some embodiments, the first circuit 2540 generates a pulse signalthrough the second circuit 2560 to make the third circuit 2580 workingin a conducting state during the pulse signal. Meanwhile, as a result,the power loop of the LED tube lamp between the installation detectionterminals 2521 and 2522 is thus conducting as well. The fourth circuit2570 detects a sample signal on the power loop and generates a signalbased on a detection result to inform the second circuit 2560 of a timepoint for latching (storing) the detection result received by the secondcircuit 2560 from the fourth circuit 2570. For example, the fourthcircuit 2570 may be a circuit configured to generate a signal thatcauses a latching circuit, such as the second circuit 2560 to enter andremain in a state that corresponds to one of a conducting state or acut-off state for the LED tube lamp. The second circuit 2560 stores thedetection result according to the detection result signal (or detectionresult signal and pulse signal), and transmits or provides the detectionresult to the third circuit 2580 coupled to the second circuit 2560 viathe fourth terminal 2561. The third circuit 2580 receives the detectionresult transmitted from the second circuit 2560 and controls the statebetween conducting or cut off between the installation detectionterminals 2521 and 2522 according to the detection result. It should benoted that the labels “first,” “second,” “third,” etc., described inconnection with these embodiments can be interchangeable and are merelyused here in order to more easily differentiate the different circuits,nodes, and other components from each other.

In some embodiments, the first circuit 2540, the second circuit 2560 andthe fourth circuit 2570 can be referred to a detection circuit or anelectric shock detection/protection circuit, which is configured tocontrol the switching state of the switch circuit/third circuit 2580. Asshown in FIG. 15B, in some embodiments, the entire detection circuitforms a detection path, and the entire detection path is part of acurrent path between the first and second external connection terminalsof the LED tube lamp and including the LED module.

Referring to FIG. 15C, a block diagram of a detection pulse generatingmodule in accordance with certain embodiments is illustrated. Adetection pulse generating module 2640 may be a circuit that includesmultiple capacitors 2642, 2645, and 2646, multiple resistors 2643, 2647,and 2648, two buffers 2644 and 2651, an inverter 2650, a diode 2649, andan OR gate 2652. The capacitor 2642 may be referred to as a firstcapacitor 2642, the capacitor 2645 may be referred to as a secondcapacitor 2645, and the capacitor 2646 may be referred to as a thirdcapacitor 2646. The resistor 2643 may be referred to as a first resistor2643, the resistor 2647 may be referred to as a second resistor 2647,and the resistor 2648 may be referred to as a third resistor 2648. Thebuffer 2644 may be referred to as a first buffer 2644 and the buffer2651 may be referred to as a second buffer 2651. The diode 2649 may bereferred to as a first diode 2649 and the OR gate 2652 may be referredto as a first OR gate 2652. With use or operation, the capacitor 2642and the resistor 2643 connect in series between a driving voltage (e.g.,a driving voltage source, which may be a node of a power supply), suchas VCC usually defined as a high logic level voltage, and a referencevoltage (or potential), such as ground potential in this embodiment. Theconnection node between the capacitor 2642 and the resistor 2643 iscoupled to an input terminal of the buffer 2644. In this exemplaryembodiment, the buffer 2644 includes two inverters connected in seriesbetween an input terminal and an output terminal of the buffer 2644. Theresistor 2647 is coupled between the driving voltage, e.g., VCC, and aninput terminal of the inverter 2650. The resistor 2648 is coupledbetween an input terminal of the buffer 2651 and the reference voltage,e.g. ground potential in this embodiment. An anode of the diode 2649 isgrounded and a cathode of the diode 2649 is coupled to the inputterminal of the buffer 2651. First ends of the capacitors 2645 and 2646are jointly coupled to an output terminal of the buffer 2644, andsecond, opposite ends of the capacitors 2645 and 2646 are respectivelycoupled to the input terminal of the inverter 2650 and the inputterminal of the buffer 2651. In this exemplary embodiment, the buffer2651 includes two inverters connected in series between an inputterminal and an output terminal of the buffer 2651. An output terminalof the inverter 2650 and an output terminal of the buffer 2651 arecoupled to two input terminals of the OR gate 2652. According to certainembodiments, the voltage (or potential) for “high logic level” and “lowlogic level” mentioned in this specification are all relative to anothervoltage (or potential) or a certain reference voltage (or potential) incircuits, and further may be described as “logic high logic level” and“logic low logic level.”

FIG. 17A is a signal waveform diagram of an exemplary power supplymodule according to an exemplary embodiment. The installation detectionoperation is described further in accordance with FIG. 17A, which showsan example when an end cap of an LED tube lamp is inserted into a lampsocket and the other end cap thereof is electrically coupled to a humanbody, or when both end caps of the LED tube lamp are inserted into thelamp socket (e.g., at the time point ts), the LED tube lamp isconductive with electricity. At this moment, the installation detectionmodule (e.g., the installation detection module 2520 as illustrated inFIG. 15A) enters a detection stage DTS. The voltage on the connectionnode of the capacitor 2642 and the resistor 2643 is high initially(equals to the driving voltage, VCC) and decreases with time to zerofinally. The input terminal of the buffer 2644 is coupled to theconnection node of the capacitor 2642 and the resistor 2643, so thebuffer 2644 outputs a high logic level signal at the beginning andchanges to output a low logic level signal when the voltage on theconnection node of the capacitor 2642 and the resistor 2643 decreases toa low logic trigger logic level. As a result, the buffer 2644 isconfigured to produce an input pulse signal and then remain in a lowlogic level thereafter (stops outputting the input pulse signal.) Thewidth for the input pulse signal may be described as equal to one(initial setting) time period, which is determined by the capacitancevalue of the capacitor 2642 and the resistance value of the resistor2643.

Next, the operations for the buffer 2644 to produce the pulse signalwith the initial setting time period will be described below. Since thevoltage on a first end of the capacitor 2645 and on a first end of theresistor 2647 is equal to the driving voltage VCC, the voltage on theconnection node of both of them is also a high logic level. The firstend of the resistor 2648 is grounded and the first end of the capacitor2646 receives the input pulse signal from the buffer 2644, so theconnection node of the capacitor 2646 and the resistor 2648 has a highlogic level voltage at the beginning but this voltage decreases withtime to zero (in the meantime, the capacitor stores the voltage beingequal to or approaching the driving voltage VCC.) Accordingly, initiallythe inverter 2650 outputs a low logic level signal and the buffer 2651outputs a high logic level signal, and hence the OR gate 2652 outputs ahigh logic level signal (a first pulse signal DP1) at the pulse signaloutput terminal 2541. At this moment, the detection result latchingcircuit 2560 (as illustrated in FIG. 15B) stores the detection resultfor the first time according to the detection result signal Sdr receivedfrom the detection determining circuit 2570 (as illustrated in FIG. 15B)and the pulse signal generated at the pulse signal output terminal 2541.During that initial pulse time period, as illustrated in FIG. 15B, thedetection pulse generating module 2540 outputs a high logic levelsignal, which results in the detection result latching circuit 2560outputting the result of that high logic level signal.

When the voltage on the connection node of the capacitor 2646 and theresistor 2648 decreases to the low logic trigger logic level, the buffer2651 changes to output a low logic level signal to make the OR gate 2652output a low logic level signal at the pulse signal output terminal 2541(stops outputting the first pulse signal DP1.) The width of the firstpulse signal DP1 output from the OR gate 2652 is determined by thecapacitance value of the capacitor 2646 and the resistance value of theresistor 2648.

The operation after the buffer 2644 stops outputting the pulse signal isdescribed as below. For example, the operation may be initially in anoperating stage DRS. Since the capacitor 2646 stores the voltage beingalmost equal to the driving voltage VCC, and when the buffer 2644instantaneously changes its output from a high logic level signal to alow logic level signal, the voltage on the connection node of thecapacitor 2646 and the resistor 2648 is below zero but will be pulled upto zero by the diode 2649 rapidly charging the capacitor 2646.Therefore, the buffer 2651 still outputs a low logic level signal.

In some embodiments, when the buffer 2644 instantaneously changes itsoutput from a high logic level signal to a low logic level signal, thevoltage on the one end of the capacitor 2645 also changes from thedriving voltage VCC to zero instantly. This makes the connection node ofthe capacitor 2645 and the resistor 2647 have a low logic level signal.At this moment, the output of the inverter 2650 changes to a high logiclevel signal to make the OR gate output a high logic level signal (asecond pulse signal DP2) at the pulse signal output terminal 2541. Thedetection result latching circuit 2560 as illustrated in FIG. 15B storesthe detection result for a second time according to the detection resultsignal Sdr received from the detection determining circuit 2570 (asillustrated in FIG. 15B) and the pulse signal generated at the pulsesignal output terminal 2541. Next, the driving voltage VCC charges thecapacitor 2645 through the resistor 2647 to make the voltage on theconnection node of the capacitor 2645 and the resistor 2647 increasewith time to the driving voltage VCC. When the voltage on the connectionnode of the capacitor 2645 and the resistor 2647 increases to reach ahigh logic trigger logic level, the inverter 2650 outputs a low logiclevel signal again to make the OR gate 2652 stop outputting the secondpulse signal DP2. The width of the second pulse signal DP2 is determinedby the capacitance value of the capacitor 2645 and the resistance valueof the resistor 2647.

As those mentioned above, in certain embodiments, the detection pulsegenerating module 2640 generates two high logic level pulse signals inthe detection stage DTS, which are the first pulse signal DP1 and thesecond pulse signal DP2. These pulse signals are output from the pulsesignal output terminal 2541. Moreover, there is an interval TIV with adefined time between the first and second pulse signals DP2 (e.g., anopposite-logic signal, which may have a low logic level when the pulsesignals have a high logic level), and the defined time is determined bythe capacitance value of the capacitor 2642 and the resistance value ofthe resistor 2643.

From the detection stage DTS entering the operating stage DRS, thedetection pulse generating module 2640 does not produce the pulse signalany more, and keeps the pulse signal output terminal 2541 on a low logiclevel potential. As described herein, the operating stage DRS is thestage following the detection stage (e.g., following the time after thesecond pulse signal DP2 ends). The operating stage DRS occurs when theLED tube lamp is at least partly connected to a power source, such asprovided in a lamp socket. For example, the operating stage DRS mayoccur when part of the LED tube lamp, such as only one side of the LEDtube lamp, is properly connected to one side of a lamp socket, and partof the LED tube lamp is either connected to a high impedance, such as aperson, and/or is improperly connected to the other side of the lampsocket (e.g., is misaligned so that the metal contacts in the socket donot contact metal contacts in the LED tube lamp). The operating stageDRS may also occur when the entire LED tube lamp is properly connectedto the lamp socket.

Referring to FIG. 15D, a detection determining circuit in accordancewith certain embodiments is illustrated. An exemplary detectiondetermining circuit 2670 includes a comparator 2671 and a resistor 2672.The comparator 2671 may also be referred to as a first comparator 2671and the resistor 2672 may also be referred to as a fifth resistor 2672.A negative input terminal of the comparator 2671 receives a referencelogic level signal (or a reference voltage) Vref, a positive inputterminal thereof is grounded through the resistor 2672 and is alsocoupled to a switch circuit coupling terminal 2581. Referring to FIGS.15B and 15D, the signal flowing into the switch circuit 2580 from theinstallation detection terminal 2521 outputs to the switch circuitcoupling terminal 2581 to the resistor 2672. When the current of thesignal passing through the resistor 2672 reaches a certain level (forexample, bigger than or equal to a defined current for installation,(e.g. 2 A) and this makes the voltage on the resistor 2672 higher thanthe reference voltage Vref (referring to two end caps inserted into thelamp socket), the comparator 2671 produces a high logic level detectionresult signal Sdr and outputs it to the detection result terminal 2571.For example, when an LED tube lamp is correctly installed on a lampsocket, the comparator 2671 outputs a high logic level detection resultsignal Sdr at the detection result terminal 2571, whereas the comparator2671 generates a low logic level detection result signal Sdr and outputsit to the detection result terminal 2571 when a current passing throughthe resistor 2672 is insufficient to make the voltage on the resistor2672 higher than the reference voltage Vref (referring to only one endcap inserted into the lamp socket.) Therefore, in some embodiments, whenthe LED tube lamp is incorrectly installed on the lamp socket or one endcap thereof is inserted into the lamp socket but the other one isgrounded by an object such as a human body, the current will be toosmall to make the comparator 2671 output a high logic level detectionresult signal Sdr to the detection result terminal 2571.

Referring to FIG. 15E, a schematic detection result latching circuitaccording to some embodiments of the present invention is illustrated. Adetection result latching circuit 2660 includes a D flip-flop 2661, aresistor 2662, and an OR gate 2663. The D flip-flop 2661 may also bereferred to as a first D flip-flop 2661, the resistor 2662 may also bereferred to as a fourth resistor 2662, and the OR gate 2663 may also bereferred to as a second OR gate 2663. The D flip-flop 2661 has a CLKinput terminal coupled to a detection result terminal 2571, and a Dinput terminal coupled to a driving voltage VCC. When the detectionresult terminal 2571 first outputs a low logic level detection resultsignal Sdr, the D flip-flop 2661 initially outputs a low logic levelsignal at a Q output terminal thereof, but the D flip-flop 2661 outputsa high logic level signal at the Q output terminal thereof when thedetection result terminal 2571 outputs a high logic level detectionresult signal Sdr. The resistor 2662 is coupled between the Q outputterminal of the D flip-flop 2661 and a reference voltage, such as groundpotential. When the OR gate 2663 receives the first or second pulsesignals DP1/DP2 from the pulse signal output terminal 2541 or receives ahigh logic level signal from the Q output terminal of the D flip-flop2661, the OR gate 2663 outputs a high logic level detection resultlatching signal at a detection result latching terminal 2561. Thedetection pulse generating module 2640 only in the detection stage DTSoutputs the first and the second pulse signals DP1/DP2 to make the ORgate 2663 output the high logic level detection result latching signal,and thus the D flip-flop 2661 decides the detection result latchingsignal to be the high logic level or the low logic level the rest of thetime, e.g., including the operating stage DRS after the detection stageDTS. Accordingly, when the detection result terminal 2571 has no highlogic level detection result signal Sdr, the D flip-flop 2661 keeps alow logic level signal at the Q output terminal to make the detectionresult latching terminal 2561 also keep a low logic level detectionresult latching signal in the detection stage DTS. On the contrary, oncethe detection result terminal 2571 has a high logic level detectionresult signal Sdr, the D flip-flop 2661 outputs and keeps a high logiclevel signal (e.g., based on VCC) at the Q output terminal. In this way,the detection result latching terminal 2561 keeps a high logic leveldetection result latching signal in the operating stage DRS as well.

Referring to FIG. 15F, a schematic switch circuit according to someembodiments is illustrated. A switch circuit 2680 includes a transistor,such as a bipolar junction transistor (BJT) 2681, as being a powertransistor, which has the ability of dealing with high current/power andis suitable for the switch circuit. The BJT 2681 may also be referred toas a first transistor 2681. The BJT 2681 has a collector coupled to aninstallation detection terminal 2521, a base coupled to a detectionresult latching terminal 2561, and an emitter coupled to a switchcircuit coupling terminal 2581. When the detection pulse generatingmodule 2640 produces the first and second pulse signals DP1/DP2, the BJT2681 is in a transient conducting state. This allows the detectiondetermining circuit 2670 to perform the detection for determining thedetection result latching signal to be a high logic level or a low logiclevel. When the detection result latching circuit 2660 outputs a highlogic level detection result latching signal at the detection resultlatching terminal 2561, this means the LED tube lamp is correctlyinstalled on the lamp socket, so that the BJT 2681 is in the conductingstate to make the installation detection terminals 2521 and 2522conducting (i.e., make the power loop conducting). In the meantime, thedriving circuit (not shown) in the power supply module starts to operatein response to the voltage received from the power loop and generatesthe lighting control signal Slc for controlling the conducting state ofthe power switch (not shown), so that the driving current can beproduced to light up the LED module. In contrast, when the detectionresult latching circuit 2660 outputs a low logic level detection resultlatching signal at the detection result latching terminal 2561 and theoutput from detection pulse generating module 2640 is a low logic level,the BJT 2681 is cut-off or in the blocking state to make theinstallation detection terminals 2521 and 2522 cut-off or blocking. Inthis case, the driving circuit of the power supply module would not bestarted, so that the lighting control signal Slc would not be generated.

Since the external driving signal Sed is an AC signal and in order toavoid the detection error resulting from the logic level of the externaldriving signal being just around zero when the detection determiningcircuit 2670 detects, the detection pulse generating module 2640generates the first and second pulse signals DP1/DP2 to let thedetection determining circuit 2670 perform two detections. So the issueof the logic level of the external driving signal being just around zeroin a single detection can be avoided. In some cases, the time differencebetween the productions of the first and second pulse signals DP1/DP2 isnot multiple times of half one cycle T of the external driving signalSed. For example, it does not correspond to the multiple phasedifferences of 180 degrees of the external driving signal Sed. In thisway, when one of the first and second pulse signals DP1/DP2 is generatedand unfortunately the external driving signal Sed is around zero, it canbe avoided that the external driving signal Sed is again around zerowhen the other pulse signal is generated.

The time difference between the productions of the first and secondpulse signals DP1/DP2, for example, an interval TIV with a defined timebetween both of them can be represented as following:

TIV=(X+Y)(T/2),

where T represents the cycle of an external driving signal Sed, X is anatural number, 0<Y<1, with Yin some embodiments in the range of0.05-0.95, and in some embodiments in the range of 0.15-0.85.

Furthermore, in order to avoid the installation detection moduleentering the detection stage DTS from misjudgment resulting from thelogic level of the driving voltage VCC being too small, the first pulsesignal DP1 can be set to be produced when the driving voltage VCCreaches or is higher than a defined logic level. For example, in someembodiments, the detection determining circuit 2670 works after thedriving voltage VCC reaches a high enough logic level in order toprevent the installation detection module from misjudgment due to aninsufficient logic level.

According to the examples mentioned above, when one end cap of an LEDtube lamp is inserted into a lamp socket and the other one floats orelectrically couples to a human body or other grounded object, thedetection determining circuit outputs a low logic level detection resultsignal Sdr because of high impedance. The detection result latchingcircuit stores the low logic level detection result signal Sdr based onthe pulse signal of the detection pulse generating module, making it asthe low logic level detection result latching signal, and keeps thedetection result in the operating stage DRS, without changing the logicvalue. In this way, the switch circuit keeps cutting-off or blockinginstead of conducting continually. And further, the electric shocksituation can be prevented and the requirement of safety standard canalso be met. On the other hand, when two end caps of the LED tube lampare correctly inserted into the lamp socket (e.g., at the time pointtd), the detection determining circuit outputs a high logic leveldetection result signal Sdr because the impedance of the circuit for theLED tube lamp itself is small. The detection result latching circuitstores the high logic level detection result signal Sdr based on thepulse signal of the detection pulse generating module, making it as thehigh logic level detection result latching signal, and keeps thedetection result in the operating stage DRS. So the switch circuit keepsconducting to make the LED tube lamp work normally in the operatingstage DRS.

In some embodiments, when one end cap of the LED tube lamp is insertedinto the lamp socket and the other one floats or electrically couples toa human body, the detection determining circuit outputs a low logiclevel detection result signal Sdr to the detection result latchingcircuit, and then the detection pulse generating module outputs a lowlogic level signal to the detection result latching circuit to make thedetection result latching circuit output a low logic level detectionresult latching signal to make the switch circuit cutting-off orblocking. As such, the switch circuit blocking makes the installationdetection terminals, e.g. the first and second installation detectionterminals, blocking. As a result, the LED tube lamp is in non-conductingor blocking state.

However, in some embodiments, when two end caps of the LED tube lamp arecorrectly inserted into the lamp socket, the detection determiningcircuit outputs a high logic level detection result signal Sdr to thedetection result latching circuit to make the detection result latchingcircuit output a high logic level detection result latching signal tomake the switch circuit conducting. As such, the switch circuitconducting makes the installation detection terminals, e.g. the firstand second installation detection terminals, conducting. As a result,the LED tube lamp operates in a conducting state.

Thus, according to the operation of the installation detection module, afirst circuit, upon connection of at least one end of the LED tube lampto a lamp socket, generates and outputs two pulses, each having a pulsewidth, with a time period between the pulses. The first circuit mayinclude various of the elements described above configured to output thepulses to a base of a transistor (e.g., a BJT transistor) that serves asa switch. The pulses occur during a detection stage DTS for detectingwhether the LED tube lamp is properly connected to a lamp socket. Thetiming of the pulses may be controlled based on the timing of variousparts of the first circuit changing from high to low logic levels, orvice versa.

The pulses can be timed such that, during that detection stage DTS time,if the LED tube lamp is properly connected to the lamp socket (e.g.,both ends of the LED tube lamp are correctly connected to conductiveterminals of the lamp socket), at least one of the pulse signals occurswhen an AC current from a driving signal is at a non-zero level. Forexample, the pulse signals can occur at intervals TIV that are differentfrom half of the period of the AC signal. For example, respective startpoints or mid points of the pulse signals, or a time between an end ofthe first pulse signal DP1 and a beginning of the second pulse signalDP2 may be separated by an amount of time that is different from half ofthe period of the AC signal (e.g., it may be between 0.05 and 0.95percent of a multiple of half of the period of the AC signal). During apulse that occurs when the AC signal is at a non-zero level, a switchthat receives the AC signal at the non-zero level may be turned on,causing a latch circuit to change states such that the switch remainspermanently on so long as the LED tube lamp remains properly connectedto the lamp socket. For example, the switch may be configured to turn onwhen each pulse is output from the first circuit. The latch circuit maybe configured to change state only when the switch is on and the currentoutput from the switch is above a threshold value, which may indicate aproper connection to a light socket. As a result, the LED tube lampoperates in a conducting state.

Accordingly, under the process of installing the LED tube lamp by auser, once the LED tube lamp is powered up (no matter whether the LEDtube lamp is lighted up or not), the installation detection module ofthe LED tube lamp generates the pulse for detecting the installationstate or the occurrence of electric shock before continuously conductingthe power loop, so that the driving current is conducted through thepower loop to drive the LED module after confirming the LED tube lamp iscorrectly installed or is not touched by the user. Therefore, the LEDtube lamp would not be lighted up until the first pulse is generated,which means the power loop would not be conducted or the current on thepower loop would be limited to less than 5 mA/MIU. In practicalapplication, the period from the time point of the LED tube lamp beingpowered up to the time point of the first pulse being generated issubstantially not less than 100 ms. For example, the LED tube lampprovided with the installation detection module of the presentembodiment does not emit light until at least 100 ms after beinginstalled and powered up. In some embodiments, since the installationdetection module continuously generates the pulses before determiningwhether the installation state is correct or determining that the userdoes not touch the LED tube lamp, the LED tube lamp will be lighted upafter at least the interval TIV (i.e., after the second pulse isgenerated) if the LED tube lamp is not lighted up after the first pulseis generated. In this example, if the LED tube lamp is not lighted upafter 100 ms, the LED tube lamp does not emit light in at least 100+TIVms as well.

It should be noted that, the LED tube lamp being powered up refers tothe external driving signal being applied to at least one pin of the LEDtube lamp and causing a current flowing through the LED tube lamp, inwhich the current can be the driving current or the leakage current.

On the other hand, if both pulses occur when a driving signal at the LEDtube lamp has a near-zero current level, or a current level below aparticular threshold, then the state of the latch circuit is notchanged, and so the switch is only on during the two pulses, but thenremains permanently off after the pulses and after the detection mode isover. For example, the latch circuit can be configured to remain in itspresent state if the current output from the switch is below thethreshold value. In this manner, the LED tube lamp remains in anon-conducting state, which prevents electric shock, even though part ofthe LED tube lamp is connected to an electrical power source.

It is worth noting that according to certain embodiments, the pulsewidth of the pulse signal generated by the detection pulse generatingmodule is between 10 μs to 1 ms, and it is used to make the switchcircuit conducting for a short period when the LED tube lamp conductsinstantaneously. In an exemplary embodiment, the pulse width of thepulse signal is between 10 μs and 30 μs. In another exemplaryembodiment, the pulse width of the pulse signal is 20 μs. In someembodiments, a pulse current is generated to pass through the detectiondetermining circuit for detecting and determining. Since the pulse isfor a short time and not for a long time, the electric shock situationwill not occur. Furthermore, the detection result latching circuit alsokeeps the detection result during the operating stage DRS (e.g., theoperating stage DRS being the period after the detection stage DTS andduring which part of the LED tube lamp is still connected to a powersource), and no longer changes the detection result stored previouslycomplying with the circuit state changing. A situation resulting fromchanging the detection result can thus be avoided. In some embodiments,the installation detection module, such as the switch circuit, thedetection pulse generating module, the detection result latchingcircuit, and the detection determining circuit, could be integrated intoa chip and then embedded in circuits for saving the circuit cost andlayout space.

In addition, although the detection pulse generating module 2640generates two pulse signals DP1 and DP2 for example, the detection pulsegenerating module 2540 of the present invention is not limited thereto.The detection pulse generating module 2540 is a circuit capable ofgenerating a single pulse or plural pulses (greater than two pulses).

For example, in some embodiments, the detection pulse generating module2640 merely includes the capacitor 2642, resistor 2643 and buffer 2644.Under such configuration, the detection pulse generating module can onlygenerate a single pulse signal DP1.

In some embodiments, the detection pulse generating module 2640 furtherincludes a reset circuit (not shown). The reset circuit may reset theoperation state of the circuits in the detection pulse generating module2640 after the first pulse signal DP1 and/or the second pulse signal DP2being generated, so that the detection pulse generating module 2640 cangenerate the first pulse signal DP1 and/or the second pulse signal DP2again after a while.

In some embodiments, the time point for generating the pulse signalDP1/DP2 can be determined by sampling the external driving signal/ACsignal and the pulse width of the pulse signal DP1/DP2 is designed to befixed. For example, the detection pulse generating module includes asampling circuit and a pulse generating circuit. The sampling circuitoutputs a pulse generating signal to the pulse generating circuit whenthe AC voltage of the external driving signal rises or falls to exceed areference voltage, so that the pulse generating circuit outputs a pulsesignal when receiving the pulse generating signal. In some embodiments,the pulse width of the pulse signal generated by the detection pulsegenerating module is between 10 μs and 1 ms, and it is used to make theswitch circuit conducting for a short period when the LED tube lampconducts instantaneously. In an exemplary embodiment, the pulse width ofthe pulse signal is between 10 μs and 30 μs. In another exemplaryembodiment, the pulse width of the pulse signal is 20 μs.

As discussed in the above examples, in some embodiments, an LED tubelamp includes an installation detection circuit comprising a firstcircuit configured to output two pulse signals, the first pulse signalDP1 output at a first time and the second pulse signal DP2 output at asecond time after the first time, and a switch configured to receive anLED driving signal and to receive the two pulse signals, wherein the twopulse signals control turning on and off of the switch. The installationdetection circuit may be configured to, during a detection stage DTS,detect during each of the two pulse signals whether the LED tube lamp isproperly connected to a lamp socket. When it is not detected duringeither pulse signal that the LED tube lamp is properly connected to thelamp socket, the switch may remain in an off state after the detectionstage DTS. When it is detected during at least one of the pulse signalsthat the LED tube lamp is properly connected to the lamp socket, theswitch may remain in an on state after the detection stage DTS. The twopulse signals may occur such that they are separated by a time differentfrom a multiple of half of a period of the LED driving signal, and suchthat at least one of them does not occur when the LED driving signal hasa current value of substantially zero. It should be noted that althougha circuit for producing two pulse signals is described, the disclosureis not intended to be limiting as such. For example, a circuit may beimplemented such that a plurality of pulse signals may occur, wherein atleast two of the plurality of pulse signals are separated by a timedifferent from a multiple of half of a period of the LED driving signal,and such that at least one of the plurality of pulse signals does notoccur when the LED driving signal has a current value of substantiallyzero.

Referring to FIG. 15G, an installation detection module according to anexemplary embodiment is illustrated. The installation detection moduleincludes a detection pulse generating module 2740 (which may also bereferred to as a detection pulse generating circuit or a first circuit),a detection result latching circuit 2760 (which may also be referred toas a second circuit), a switch circuit 2780 (which may also be referredto as a third circuit), and a detection determining circuit 2770 (whichmay also be referred to as a fourth circuit). In some embodiments, thefirst circuit 2740, the second circuit 2760 and the fourth circuit 2770can be referred to a detection circuit or an electric shockdetection/protection circuit, which is configured to control theswitching state of the switch circuit/third circuit 2780.

FIG. 17B is a signal waveform diagram of an exemplary power supplymodule according to an exemplary embodiment. The installation detectionoperation is described further in accordance with FIG. 17B. Thedetection pulse generating module 2740 is coupled (e.g., electricallyconnected) to the detection result latching circuit 2760 via a path2741, and is configured to generate a control signal Sc having at leastone pulse signal DP. A path as described herein may include a conductiveline connecting between two components, circuits, or modules, and mayinclude opposite ends of the conductive line connected to the respectivecomponents, circuits or modules. The detection result latching circuit2760 is coupled (e.g., electrically connected) to the switch circuit2780 via a path 2761, and is configured to receive and output thecontrol signal Sc from the detection pulse generating module 2740. Theswitch circuit 2780 is coupled (e.g., electrically connected) to one end(e.g., a first installation detection terminal 2521) of a power loop ofan LED tube lamp and the detection determining circuit 2770, and isconfigured to receive the control signal Sc output from the detectionresult latching circuit 2760, and configured to conduct (or turn on)during the control signal Sc so as to cause the power loop of the LEDtube lamp to be conducting. The detection determining circuit 2770 iscoupled (e.g., electrically connected) to the switch circuit 2780, theother end (e.g., a second installation detection terminal 2522) of thepower loop of the LED tube lamp and the detection result latchingcircuit 2760, and is configured to detect at least one sample signal Sspon the power loop when the switch circuit 2780 and the power loop areconductive, so as to determine an installation state between the LEDtube lamp and a lamp socket. The power loop of the present embodimentcan be regarded as a detection path of the installation detectionmodule. The detection determining circuit 2770 is further configured totransmit detection result(s) to the detection result latching circuit2760 for next control. In some embodiments, the detection pulsegenerating module 2740 is further coupled (e.g., electrically connected)to the output of the detection result latching circuit 2760 to controlthe time of the pulse signal DP.

In some embodiments, one end of a first path 2781 is coupled to a firstnode of the detection determining circuit 2770 and the opposite end ofthe first path 2781 is coupled to a first node of the switch circuit2780. In some embodiments, a second node of the detection determiningcircuit 2770 is coupled to the second installation detection terminal2522 of the power loop and a second node of the switch circuit 2780 iscoupled to the first installation detection terminal 2521 of the powerloop. In some embodiments, one end of a second path 2771 is coupled to athird node of the detection determining circuit 2770 and the oppositeend of the second path 2771 is coupled to a first node of the detectionresult latching circuit 2760, one end of a third path 2741 is coupled toa second node of the detection result latching circuit 2760 and theopposite end of the third path 2741 is coupled to a first node of thedetection pulse generating circuit 2740. In some embodiments, one end ofa fourth path 2761 is coupled to a third node of the switch circuit 2780and the opposite end of the fourth path 2761 is coupled to a third nodeof the detection result latching circuit 2760. In some embodiments, thefourth path 2761 is also coupled to a second node of the detection pulsegenerating circuit 2740.

In some embodiments, the detection determining circuit 2770 isconfigured for detecting a signal between the first installationdetection terminal 2521 and the second installation detection terminal2522 through the first path 2781 and the switch circuit 2780. Forexample, because of the above configuration, the detection determiningcircuit 2770 is capable of detecting and determining whether a currentpassing through the first installation detection terminal 2521 and thesecond installation detection terminal 2522 is below or above apredetermined current value and transmitting or providing a detectionresult signal Sdr to the detection result latching circuit 2760 via thesecond path 2771.

In some embodiments, the detection pulse generating circuit 2740, alsoreferred to generally as a pulse generating circuit, generates a pulsesignal DP through the detection result latching circuit 2760 to make theswitch circuit 2780 remain in a conducting state during the pulsesignal. For example, the pulse signal DP generated by the detectionpulse generating circuit 2740 controls turning on the switch circuit2780 which is coupled to the detection pulse generating circuit 2740. Asa result of maintaining a conducting state of the switch circuit 2780,the power loop of the LED tube lamp between the installation detectionterminals 2521 and 2522 is also maintained in a conducting state. Thedetection determining circuit 2770 detects a sample signal Ssp on thepower loop and generates a signal based on a detection result to informthe detection result latching circuit 2760 of a time point for latching(storing) the detection result received by the detection result latchingcircuit 2760 from the detection determining circuit 2770. For example,the detection determining circuit 2770 may be a circuit configured togenerate a signal that causes a latching circuit, such as the detectionresult latching circuit 2760 to enter and remain in a state thatcorresponds to one of a conducting state (e.g., “on” state) and acut-off state for the LED tube lamp. The detection result latchingcircuit 2760 stores the detection result according to the detectionresult signal Sdr (or detection result signal Sdr and pulse signalDP1/DP2), and transmits or provides the detection result to the switchcircuit 2780 coupled to the third node of the detection result latchingcircuit 2760 via the fourth path 2761. The switch circuit 2780 receivesthe detection result transmitted from the detection result latchingcircuit 2760 via the third node of the switch circuit 2780 and controlsthe state between conducting or cut off between the installationdetection terminals 2521 and 2522 according to the detection result. Forexample, when the detection determining circuit 2770 detects during thepulse signal DP that the LED tube lamp is not properly installed on thelamp socket, the pulse signal DP controls the switch circuit 2780 toremain in an off state to cause a power loop of the LED tube lamp to beopen, and when the detection determining circuit 2770 detects during thepulse signal DP that the LED tube lamp is properly installed on the lampsocket, the pulse signal DP controls the switch circuit 2780 to remainin a conducting state to cause the power loop of the LED tube lamp tomaintain a conducting state.

The detailed circuit structure and the entire operation thereof of eachof the detection pulse generating module 2740 (or circuit), thedetection result latching circuit 2760, the switch circuit 2780, and thedetection determining circuit 2770 will be described below.

Referring to FIG. 15H, a detection pulse generating module according toan exemplary embodiment is illustrated. The detection pulse generatingmodule 2740 includes: a resistor 2742 (which also may be referred to asa sixth resistor), a capacitor 2743 (which also may be referred to as afourth capacitor), a Schmitt trigger 2744, a resistor 2745 (which alsomay be referred to as a seventh resistor), a transistor 2746 (which alsomay be referred to as a second transistor), and a resistor 2747 (whichalso may be referred to as an eighth resistor).

In some embodiments, one end of the resistor 2742 is connected to adriving signal, for example, Vcc, and the other end of the resistor 2742is connected to one end of the capacitor 2743. The other end of thecapacitor 2743 is connected to a ground node. In some embodiments, theSchmitt trigger 2744 has an input end and an output end, the input endconnected to a connection node of the resistor 2742 and the capacitor2743, the output end connected to the detection result latching circuit2760 via the third path 2741 (FIG. 15G). In some embodiments, one end ofthe resistor 2745 is connected to the connection node of the resistor2742 and the capacitor 2743 and the other end of the resistor 2745 isconnected to a collector of the transistor 2746. An emitter of thetransistor 2746 is connected to a ground node. In some embodiments, oneend of the resistor 2747 is connected to a base of the transistor 2746and the other end of the resistor 2747 is connected to the detectionresult latching circuit 2760 (FIG. 15G) and the switch circuit 2780(FIG. 15G) via the fourth path 2761. In certain embodiments, thedetection pulse generating module 2740 further includes: a Zener diode2748, having an anode and a cathode, the anode connected to the otherend of the capacitor 2743 to the ground, the cathode connected to theend of the capacitor 2743 (the connection node of the resistor 2742 andthe capacitor 2743).

Referring to FIG. 15I, a detection result latching circuit according toan exemplary embodiment is illustrated. The detection result latchingcircuit 2760 includes: a D flip-flop 2762 (which also may be referred toas a second D flip-flop), having a data input end D, a clock input endCLK, and an output end Q, the data input end D connected to the drivingsignal mentioned above (e.g., Vcc), the clock input end CLK connected tothe detection determining circuit 2770 (FIG. 15G); and an OR gate 2763(which also may be referred to as a third OR gate), having a first inputend, a second input end, and an output end, the first input endconnected to the output end of the Schmitt trigger 2744 (FIG. 15H), thesecond input end connected to the output end Q of the D flip-flop 2762,the output end of the OR gate 2763 connected to the other end of theresistor 2747 (FIG. 15H) and the switch circuit 2780 (FIG. 15G).

Referring to FIG. 15J, a switch circuit according to an exemplaryembodiment is illustrated. The switch circuit 2780 includes: atransistor 2782 (which also may be referred to as a third transistor),having a base, a collector, and an emitter, the base connected to theoutput of the OR gate 2763 via the fourth path 2761 (FIG. 15I), thecollector connected to one end of the power loop, such as the firstinstallation detection terminal 2521, the emitter connected to thedetection determining circuit 2770 (FIG. 15G). In some embodiments, thetransistor 2782 may be replaced by other equivalently electronic parts,e.g., a MOSFET.

Referring to FIG. 15K, a detection determining circuit according to anexemplary embodiment is illustrated. The detection determining circuit2770 includes: a resistor 2774 (which also may be referred to as a ninthresistor), one end of the resistor 2774 connected to the emitter of thetransistor 2782 (FIG. 15J), the other end of the resistor 2774 connectedto the other end of the power loop, such as the second installationdetection terminal 2522; a diode 2775 (which also may be referred to asa second diode), having an anode and a cathode, the anode connected toan end of the resistor 2744 that is not connected to a ground node; acomparator 2772 (which also may be referred to as a second comparator),having a first input end, a second input end, and an output end; acomparator 2773 (which also may be referred to as a third comparator),having a first input end, a second input end, and an output end; aresistor 2776 (which also may be referred to as a tenth resistor); aresistor 2777 (which also may be referred to as an eleventh resistor);and a capacitor 2778 (which also may be referred to as a fifthcapacitor).

In some embodiments, the first input end of the comparator 2772 isconnected to a predefined signal, for example, a reference voltage,Vref=1.3V, but the reference voltage value is not limited thereto, thesecond input end of the comparator 2772 is connected to the cathode ofthe diode 2775, and the output end of the comparator 2772 is connectedto the clock input end of the D flip-flop 2762 (FIG. 15I). In someembodiments, the first input end of the comparator 2773 is connected tothe cathode of the diode 2775, the second input end of the comparator2773 is connected to another predefined signal, for example, a referencevoltage, Vref=0.3V, but the reference voltage value is not limitedthereto, and the output end of the comparator 2773 is connected to theclock input end of the D flip-flop 2762 (FIG. 15I). In some embodiments,one end of the resistor 2776 is connected to the driving signalmentioned above (e.g., Vcc) and the other end of the resistor 2776 isconnected to the second input end of the comparator 2772 and one end ofthe resistor 2777 that is not connected to a ground node and the otherend of the resistor 2777 is connected to the ground node. In someembodiments, the capacitor 2778 is connected to the resistor 2777 inparallel. In certain embodiments, the diode 2775, the comparator 2773,the resistors 2776 and 2777, and the capacitor 2778 may be omitted, andthe second input end of the comparator 2772 may be directly connected tothe end of the resistor 2774 (e.g., the end of the resistor 2774 that isnot connected to the ground node) when the diode 2775 is omitted. Incertain embodiments, the resistor 2774 may include two resistorsconnected in parallel based on the consideration of power consumptionhaving an equivalent resistance value ranging from about 0.1 ohm toabout 5 ohm.

In some embodiments, some parts of the installation detection module maybe integrated into an integrated circuit (IC) in order to providereduced circuit layout space resulting in reduced manufacturing cost ofthe circuit. For example, the Schmitt trigger 2744 of the detectionpulse generating module 2740, the detection result latching circuit2760, and the two comparators 2772 and 2773 of the detection determiningcircuit 2770 may be integrated into an IC, but the disclosure is notlimited thereto.

An operation of the installation detection module will be described inmore detail in accordance with some example embodiments. In oneexemplary embodiment, the capacitor voltage may not mutate; the voltageof the capacitor in the power loop of the LED tube lamp before the powerloop is conductive is zero and the capacitor's transient response mayappear to have a short-circuit condition; when the LED tube lamp iscorrectly installed to the lamp socket, the power loop of the LED tubelamp in a transient response may have a smaller current-limitingresistance and a bigger peak current; and when the LED tube lamp isincorrectly installed to the lamp socket, the power loop of the LED tubelamp in transient response may have a bigger current-limiting resistanceand a smaller peak current. This embodiment may also meet the ULstandard to make the leakage current of the LED tube lamp less than 5MIU (Measurement Indication Unit), in which the unit “MIU” is definedby. The following table illustrates the current comparison in a casewhen the LED tube lamp works normally (e.g., when the two end caps ofthe LED tube lamp are correctly installed to the lamp socket) and in acase when the LED tube lamp is incorrectly installed to the lamp socket(e.g., when one end cap of the LED tube lamp is installed to the lampsocket but the other one is touched by a human body).

Correct installation Incorrect installation Maximum transient current$i_{{pk}\_ \max} = {\frac{V_{{in}\_ {pk}}}{R_{fuse} + 500} = {\frac{305 \times 1.414}{10 + 500} = {845\mspace{14mu} {mA}}}}$Minimum transient current$i_{{pk}\_ \min} = {\frac{{\Delta V}_{in}}{R_{fuse}} = {\frac{50}{10} = {5\mspace{14mu} A}}}$

As illustrated in the above table, in the part of the denominator: Rfuserepresents the resistance of the fuse of the LED tube lamp. For example,10 ohm may be used, but the disclosure is not limited thereto, asresistance value for Rfuse in calculating the minimum transient currentipk_min and 510 ohm may be used as resistance value for Rfuse incalculating the maximum transient current ipk_max (an additional 500ohms is used to emulate the conductive resistance of human body intransient response). In the part of the numerator: maximum voltage fromthe root-mean-square voltage (Vmax=Vrms*1.414=305*1.414) is used incalculating the maximum transient current ipk_max and minimum voltagedifference, for example, 50V (but the disclosure is not limited thereto)is used in calculating the minimum transient current ipk_min.Accordingly, when the LED tube lamp is correctly installed to the lampsocket (e.g., when two end caps of the LED tube lamp are installed tothe lamp socket correctly) and works normally, its minimum transientcurrent is 5 A. But, when the LED tube lamp is incorrectly installed tothe lamp socket (e.g., when one end cap is installed to the lamp socketbut the other one is touched by human body), its maximum transientcurrent is only 845 mA. Therefore, certain examples of the disclosedembodiments use the current which passes transient response and flowsthrough the capacitor in the LED power loop, such as the capacitor ofthe filtering circuit, to detect and determine the installation statebetween the LED tube lamp and the lamp socket. For example, suchembodiments may detect whether the LED tube lamp is correctly installedto the lamp socket. Certain examples of the disclosed embodimentsfurther provide a protection mechanism to protect the user from electricshock caused by touching the conductive part of the LED tube lamp whichis incorrectly installed to the lamp socket. The embodiments mentionedabove are used to illustrate certain aspects of the disclosed inventionbut the disclosure is not limited thereto.

Further, referring to FIG. 15G again, in some embodiments, when an LEDtube lamp is being installed to a lamp socket, after a period (e.g., theperiod utilized to determine the cycle of a pulse signal), the detectionpulse generating module 2740 outputs a first high level voltage risingfrom a first low level voltage to the detection result latching circuit2760 through a path 2741 (also referred to as a third path). Thedetection result latching circuit 2760 receives the first high levelvoltage, and then simultaneously outputs a second high level voltage tothe switch circuit 2780 and the detection pulse generating module 2740through a path 2761 (also referred to as a fourth path). In someembodiments, when the switch circuit 2780 receives the second high levelvoltage, the switch circuit 2780 conducts to cause the power loop of theLED tube lamp to be conducting as well. In this exemplary embodiment,the power loop at least includes the first installation detectionterminal 2521, the switch circuit 2780, the path 2781 (also referred toas a first path), the detection determining circuit 2770, and the secondinstallation detection terminal 2522. In the meantime, the detectionpulse generating module 2740 receives the second high level voltage fromthe detection result latching circuit 2760, and after a period (e.g.,the period utilized to determine the width (or period) of pulse signal),its output from the first high level voltage falls back to the first lowlevel voltage (the first time of the first low level voltage, the firsthigh level voltage, and the second time of the first low level voltageform a first pulse signal DP1). In some embodiments, when the power loopof the LED tube lamp is conductive, the detection determining circuit2770 detects a first sample signal, such as a voltage signal, on thepower loop. When the first sample signal is greater than or equal to apredefined signal, such as a reference voltage, the installationdetection module determines that the LED tube lamp is correctlyinstalled to the lamp socket according to the application principle ofthis disclosed embodiments described above. Therefore, the detectiondetermining circuit 2770 included in the installation detection moduleoutputs a third high level voltage (also referred to as a first highlevel signal) to the detection result latching circuit 2760 through apath 2771 (also referred to as a second path). The detection resultlatching circuit 2760 receives the third high level voltage (alsoreferred to as the first high level signal) and continues to output asecond high level voltage (also referred to as a second high levelsignal) to the switch circuit 2780. The switch circuit 2780 receives thesecond high level voltage (also referred to as the second high levelsignal) and maintains conducting state to cause the power loop to remainconducting. The detection pulse generating module 2740 does not generateany pulse signal while the power loop remains conductive.

However, in some embodiments, when the first sample signal is smallerthan the predefined signal, the installation detection module, accordingto certain exemplary embodiments as described above, determines that theLED tube lamp has not been correctly installed to the lamp socket.Therefore, the detection determining circuit 2770 outputs a third lowlevel voltage (also referred to as a first low level signal) to thedetection result latching circuit 2760. The detection result latchingcircuit 2760 receives the third low level voltage (also referred to asthe first low level signal) and continues to output a second low levelvoltage (also referred to as a second low level signal) to the switchcircuit 2780. The switch circuit 2780 receives the second low levelvoltage (also referred to as the second low level signal) and then keepsblocking to cause the power loop to remain open. Accordingly, theoccurrence of electric shock caused by touching the conductive part ofthe LED tube lamp which is incorrectly installed on the lamp socket canbe sufficiently avoided.

In some embodiments, when the power loop of the LED tube lamp remainsopen for a period (a period that represents the width (or period) ofpulse signal DP or the pulse-on time of the control signal Sc), thedetection pulse generating module 2740 outputs the first high levelvoltage rising from the first low level voltage to the detection resultlatching circuit 2760 through the path 2741 once more. The detectionresult latching circuit 2760 receives the first high level voltage, andthen simultaneously outputs a second high level voltage to the switchcircuit 2780 and the detection pulse generating module 2740. In someembodiments, when the switch circuit 2780 receives the second high levelvoltage, the switch circuit 2780 conducts again to cause the power loopof the LED tube lamp (in this exemplary embodiment, the power loop atleast includes the first installation detection terminal 2521, theswitch circuit 2780, the path 2781, the detection determining circuit2770, and the second installation detection terminal 2522) to beconducting as well. In the meantime, the detection pulse generatingmodule 2740 receives the second high level voltage from the detectionresult latching circuit 2760, and after a period (a period that isutilized to determine the width (or period) of pulse signal DP), itsoutput from the first high level voltage falls back to the first lowlevel voltage (the third time of the first low level voltage, the secondtime of the first high level voltage, and the fourth time of the firstlow level voltage form a second pulse signal DP2). In some embodiments,when the power loop of the LED tube lamp is conductive again, thedetection determining circuit 2770 also detects a second sample signalSP2, such as a voltage signal, on the power loop yet again. When thesecond sample signal SP2 is greater than or equal to the predefinedsignal (e.g., the reference voltage Vref), the installation detectionmodule determines, according to certain exemplary embodiments describedabove, that the LED tube lamp is correctly installed to the lamp socket.Therefore, the detection determining circuit 2770 outputs a third highlevel voltage (also referred to as a first high level signal) to thedetection result latching circuit 2760 through the path 2771. Thedetection result latching circuit 2760 receives the third high levelvoltage (also referred to as the first high level signal) and continuesto output a second high level voltage (also referred to as a second highlevel signal) to the switch circuit 2780. The switch circuit 2780receives the second high level voltage (also referred to as the secondhigh level signal) and maintains a conducting state to cause the powerloop to remain conducting. The detection pulse generating module 2740does not generate any pulse signal while the power loop remainsconductive.

In some embodiments, when the second sample signal SP2 is smaller thanthe predefined signal, the installation detection module determines,according to certain exemplary embodiments described above, that the LEDtube lamp has not been correctly installed to the lamp socket.Therefore, the detection determining circuit 2770 outputs the third lowlevel voltage (also referred to as the first low level signal) to thedetection result latching circuit 2760. The detection result latchingcircuit 2760 receives the third low level voltage (also referred to asthe first low level signal) and continues to output the second low levelvoltage (also referred to as the second low level signal) to the switchcircuit 2780. The switch circuit 2780 receives the second low levelvoltage (also referred to as the second low level signal) and then keepsblocking to cause the power loop to remain open. According to thedisclosure mentioned above, the pulse width (i.e., pulse on-time) andthe pulse period are dominated by the pulse signal provided by thedetection pulse generating module 2740 during the detection stage DTS;and the signal level of the control signal is determined according tothe detection result signal Sdr provided by the detection determiningcircuit 2770 after the detection stage DTS.

According to the embodiments of FIG. 17B, since the signal level of thefirst sample signal SP1 generated based on the first pulse signal DP1and the second sample signal SP2 generated based on the second pulsesignal DP2 are smaller than the reference voltage Vref, the switchcircuit 2780 is maintained to be cut off and the driving circuit (notshown) does not perform effective power conversion during the time pointis to td (i.e., the detection stage DTS). The effective power conversionrefers to generating sufficient power for driving the LED module to emitlight. The detection determining circuit 2770 generates a detectionresult, indicating the LED tube lamp has been correctly installed or isnot touched by a user, according to the third sample signal SP3 greaterthan the reference voltage Vref during the pulse-on time of the thirdpulse signal DP3, so that the switch circuit 2780 is maintained in theconducting state in response to the high level voltage output by thedetection result latching circuit 2760 and the power loop is thereforemaintained in the conducting state as well. After the power loop isconducting, the driving circuit of the power supply module starts tooperate based on the voltage on the power loop, so as to generate thelighting control signal Slc for controlling the conducting state of thepower switch (not shown).

Next, referring to FIG. 15H to FIG. 15K at the same time, in someembodiments when an LED tube lamp is being installed to a lamp socket,the capacitor 2743 is charged by the driving signal, for example, Vcc,through the resistor 2742. And when the voltage of the capacitor 2743rises enough to trigger the Schmitt trigger 2744, the Schmitt trigger2744 outputs a first high level voltage rising from a first low levelvoltage in an initial state to an input end of the OR gate 2763. Afterthe OR gate 2763 receives the first high level voltage from the Schmitttrigger 2744, the OR gate 2763 outputs a second high level voltage tothe base of the transistor 2782 and the resistor 2747. When the base ofthe transistor 2782 receives the second high level voltage from the ORgate 2763, the collector and the emitter of the transistor 2782 areconducting to further cause the power loop of the LED tube lamp (in thisexemplary embodiment, the power loop at least includes the firstinstallation detection terminal 2521, the transistor 2782, the resistor2744, and the second installation detection terminal 2522) to beconducting as well. In the meantime, the base of the transistor 2746receives the second high level voltage from the OR gate 2763 through theresistor 2747, and then the collector and the emitter of the transistor2746 are conductive and grounded to cause the voltage of the capacitor2743 to be discharged to the ground through the resistor 2745. In someembodiments, when the voltage of the capacitor 2743 is not enough totrigger the Schmitt trigger 2744, the Schmitt trigger 2744 outputs thefirst low level voltage falling from the first high level voltage (afirst instance of a first low level voltage at a first time, followed bya first high level voltage, followed by a second instance of the firstlow level voltage at a second time form a first pulse signal DP1). Whenthe power loop of the LED tube lamp is conductive, the current passingthrough the capacitor in the power loop, such as, the capacitor of thefiltering circuit, by transient response flows through the transistor2782 and the resistor 2774 and forms a voltage signal on the resistor2774. The voltage signal is compared to a reference voltage, forexample, 1.3V, but the reference voltage is not limited thereto, by thecomparator 2772. When the voltage signal is greater than and/or equal tothe reference voltage, the comparator 2772 outputs a third high levelvoltage to the clock input end CLK of the D flip-flop 2762. In themeantime, since the data input end D of the D flip-flop 2762 isconnected to the driving signal, the D flip-flop 2762 outputs a highlevel voltage (at its output end Q) to another input end of the OR gate2763. This causes the OR gate 2763 to keep outputting the second highlevel voltage to the base of the transistor 2782, and further results inthe transistor 2782 and the power loop of the LED tube lamp remaining ina conducting state. Besides, since the OR gate 2763 keeps outputting thesecond high level voltage to cause the transistor 2746 to be conductingto the ground, the capacitor 2743 is unable to reach an enough voltageto trigger the Schmitt trigger 2744.

However, when the voltage signal on the resistor 2774 is smaller thanthe reference voltage, the comparator 2772 outputs a third low levelvoltage to the clock input end CLK of the D flip-flop 2762. In themeantime, since the initial output of the D flip-flop 2762 is a lowlevel voltage (e.g., zero voltage), the D flip-flop 2762 outputs a lowlevel voltage (at its output end Q) to the other input end of the ORgate 2763. Moreover, the Schmitt trigger 2744 connected by the input endof the OR gate 2763 also restores outputting the first low levelvoltage, the OR gate 2763 thus keeps outputting the second low levelvoltage to the base of the transistor 2782, and further results in thetransistor 2782 to remain in a blocking state (or an off state) and thepower loop of the LED tube lamp to remain in an open state. Still, sincethe OR gate 2763 keeps outputting the second low level voltage to causethe transistor 2764 to remain in a blocking state (or an off state), thecapacitor 2743 is charged by the driving signal through the resistor2742 once again for next (pulse signal) detection.

In some embodiments, the cycle (or interval) of the pulse signal isdetermined by the values of the resistor 2742 and the capacitor 2743. Incertain cases, the cycle of the pulse signal may include a value rangingfrom about 3 milliseconds to about 500 milliseconds or may be rangingfrom about 20 milliseconds to about 50 milliseconds. In someembodiments, the width (or period) of the pulse signal is determined bythe values of the resistor 2745 and the capacitor 2743. In certaincases, the width of the pulse signal may include a value ranging fromabout 1 microsecond to about 100 microseconds or may be ranging fromabout 10 microseconds to about 20 microseconds. The Zener diode 2748provides a protection function but it may be omitted in certain cases.The resistor 2744 may include two resistors connected in parallel basedon the consideration of power consumption in certain cases, and itsequivalent resistance may include a value ranging from about 0.1 ohm toabout 5 ohm. The resistors 2776 and 2777 provides the function ofvoltage division to make the input of the comparator 2773 bigger thanthe reference voltage, such as 0.3V, but the value of the referencevoltage is not limited thereto. The capacitor 2778 provides thefunctions of regulation and filtering. The diode 2775 limits the signalto be transmitted in one way. In addition, the installation detectionmodule disclosed by the example embodiments may also be adapted to othertypes of LED lighting equipment with dual-end power supply, e.g., theLED lamp directly using commercial power as its external driving signal,the LED lamp using the signal outputted from the ballast as its externaldriving signal, etc. However, the invention is not limited to the aboveexample embodiments.

Based on the embodiments illustrated in FIG. 15G to FIG. 15K, comparedto the installation detection module of FIG. 15B, the installationdetection module illustrated in FIG. 15G uses the control signal outputby the detection result latching circuit 2760 for the reference ofdetermining the end of the pulse or resetting the pulse signal byfeeding back the control signal to the detection pulse generating module2740. Since the pulse on-time is not merely determined by the detectionpulse generating module 2740, the circuit design of the detection pulsegenerating module can be simplified. Compared to the detection pulsegenerating module illustrated in FIG. 15C, the number of the componentsof the detection pulse generating module illustrated in FIG. 15H is lessthan the detection pulse generating module 2640, and thus the detectionpulse generating module 2740 may have lower power consumption and may bemore suitable for integrated design.

Referring to FIG. 15L, a block diagram of an installation detectionmodule according to an exemplary embodiment is illustrated. Theinstallation detection module 2520 includes a pulse generating auxiliarycircuit 2840, an integrated control module 2860, a switch circuit 2880,and a detection determining auxiliary circuit 2870. The operation of theinstallation detection module of the present embodiment is similar tothe embodiment of FIGS. 15G to 15K, and thus the signal waveform of thepresent embodiment can refer to the embodiment illustrated in FIG. 17B.The integrated control module 2860 includes at least three pins such astwo input terminals IN1 and IN2 and an output terminal OT. The pulsegenerating auxiliary circuit 2840 is connected to the input terminal IN1and the output terminal OT of the integrated control module 2860 andconfigured to assist the integrated control module 2860 for generating acontrol signal. The detection determining auxiliary circuit 2870 isconnected to the input terminal IN2 of the integrated control module2860 and the switch circuit 2880 and configured to transmit a samplesignal related to the signal passing through the LED power loop to theinput terminal IN2 of the integrated control module 2860 when the switchcircuit 2880 and the LED power loop are conducting, such that theintegrated control module 2860 may determine an installation statebetween the LED tube lamp and the lamp socket according to the samplesignal. For example, the sample signal may be based on an electricalsignal passing through the power loop during the pulse-on time of thepulse signal (e.g., the rising portion of the pulse signal). Switchcircuit 2880 is connected between one end of the LED power loop and thedetection determining auxiliary circuit 2870 and configured to receivethe control signal, outputted by the integrated control module 2860, inwhich the LED power loop is conducting during an enable period of thecontrol signal (i.e., the pulse-on time).

Specifically, under the detection stage DTS, the integrated controlmodule 2860 temporarily causes the switch circuit 2880 to conduct,according to the signal received from the input terminal IN1, byoutputting the control signal having at least one pulse. During thedetection stage DTS, the integrated control module 2860 may detectwhether the LED tube lamp is properly connected to the lamp socket andlatch the detection result according to the signal on the input terminalIN2. The detection result is regarded as the basis of whether to causethe switch circuit 2880 to conduct after the detection stage DTS (i.e.,it determines whether to provide power to LED module). The detailcircuit structure and operations of the present embodiment will bedescribed below.

Referring to FIG. 15M, an inner circuit diagram of an integrated controlmodule according to some exemplary embodiments is illustrated. Theintegrated control module includes a pulse generating unit 2862, adetection result latching unit 2863, and a detection unit 2864. Thepulse generating unit 2862 receives the signal provided by the pulsegenerating auxiliary circuit 2840 from the input terminal IN1 andaccordingly generates a pulse signal. The generated pulse signal will beprovided to the detection result latching unit 2863. In an exemplaryembodiment, the pulse generating unit 2862 can be implemented by aSchmitt trigger (not shown, it can use a Schmitt trigger such as 2744illustrated in FIG. 15H). According to the exemplary embodimentmentioned above, the Schmitt trigger has an input end coupled to theinput terminal IN1 of the integrated control module 2860 and an outputterminal coupled to the output terminal OT of the integrated controlmodule 2860 (e.g., through the detection result latching unit 2863). Itshould be noted that, the pulse generating unit 2862 is not limited tobe implemented by the Schmitt trigger, any analog/digital circuitcapable of implementing the function of generating the pulse signalhaving at least one pulse may be utilized in the disclosed embodiments.

The detection result latching unit 2863 is connected to the pulsegenerating unit 2862 and the detection unit 2864. During the detectionstage DTS, the detection result latching unit 2863 outputs the pulsesignal generated by the pulse generating unit 2862 as the control signalto the output terminal OT. On the other hand, the detection resultlatching unit 2863 further stores the detection result signal Sdrprovided by the detection unit 2864 and outputs the stored detectionresult signal Sdr to the output terminal OT after the detection stageDTS, so as to determine whether to cause the switch circuit 2880 toconduct according to the installation state of the LED tube lamp. In anexemplary embodiment, the detection latching unit 2863 can beimplemented by a circuit structure constituted by a D flip-flop and anOR gate (not shown, for example it can use the D flip-flop 2762 and ORgate 2763 illustrated in FIG. 15I). According to the exemplaryembodiment mentioned above, the D flip-flop has a data input endconnected to the driving voltage VCC, a clock input end connected to thedetection unit 2864, and an output end. The OR gate has a first inputend connected to the pulse generating unit 2862, a second input endconnected to the output end of the D flip-flop, and an output endconnected to the output terminal OT. It should be noted that, thedetection result latching unit 2863 is not limited to be implemented bythe aforementioned circuit structure, any analog/digital circuit capableof implementing the function of latching and outputting the controlsignal to control the switching of the switch circuit may be utilized inthe present invention.

The detection unit 2864 is coupled to the detection result latching unit2863. The detection unit 2864 receives the signal provided by thedetection determining auxiliary circuit 2870 from the input terminal IN2and accordingly generates the detection result signal Sdr indicating theinstallation state of the LED tube lamp, in which the generateddetection result signal Sdr will be provided to the detection resultlatching unit 2863. In an exemplary embodiment, detection unit 2864 canbe implemented by a comparator (not shown, it can be, for example, thecomparator 2772 illustrated in FIG. 15K). According to the exemplaryembodiment mentioned above, the comparator has a first input endreceiving a setting signal, a second input end connected to the inputterminal IN2, and an output end connected to the detection resultlatching unit 2863. It should be noted that, the detection unit 2864 isnot limited to be implemented by the comparator, any analog/digitalcircuit capable of implementing the function of determining theinstallation state based on the signal on the input terminal IN2 may beutilized in the disclosed embodiments.

Referring to FIG. 15N, a circuit diagram of a pulse generating auxiliarycircuit according to some exemplary embodiments is illustrated. Thepulse generating auxiliary circuit 2840 includes resistors 2842, 2844,and 2846, a capacitor 2843, and a transistor 2845. The resistor 2842 hasan end connected to a driving voltage (e.g., VCC). The capacitor 2843has an end connected to another end of the resistor 2842, and anotherend connected to ground. The resistor 2844 has an end connected to theconnection node of the resistor 2842 and the capacitor 2843. Thetransistor 2845 has a base, a collector connected to another end of theresistor 2844, and an emitter connected to the ground. The resistor 2846has an end connected to the base of the transistor 2845, and another endconnected to the output terminal OT of the integrated control module2840 and the control terminal of the switch circuit 2880 via the path2841. The pulse generating auxiliary circuit 2840 further includes aZener diode 2847. The Zener diode 2847 has an anode connected to anotherend of the capacitor 2843 and the ground and a cathode connected to theend connecting the capacitor 2843 and the resistor 2842.

Referring to FIG. 15O, a circuit diagram of a detection determiningauxiliary circuit according to some exemplary embodiments isillustrated. The detection determining auxiliary circuit 2870 includesresistors 2872, 2873 and 2874, a capacitor 2875 and diode 2876. Theresistor 2872 has an end connected to the switch circuit 2880, andanother end connected to another end of the LED power loop (e.g., thesecond installation detection terminal 2522). The resistor 2873 has anend connected to the driving voltage (e.g., VCC). The resistor 2874 hasan end connected to another end of the resistor 2873 and the inputterminal IN2 of the integrated control module 2860 via the path 2871,and another end connected to the ground. The capacitor 2875 is connectedto the resistor 2874 in parallel. The diode 2876 has an anode connectedto the end of the resistor 2872 and a cathode connected to theconnection node of the resistors 2873 and 2874. In one exemplaryembodiment, the resistors 2873 and 2874, the capacitor 2875, and thediode 2876 can be omitted. When the diode 2876 is omitted, one end ofthe resistor 2872 is directly connected to the input terminal IN2 of theintegrated control module 2860 via the path 2871. In another oneexemplary embodiment, the resistor 2872 can be implemented by twoparalleled resistors based on the power consideration, in which theequivalent resistance of each resistors can be 0.1 ohm to 5 ohm.

Referring to FIG. 15P, a circuit diagram of a switch circuit accordingto some exemplary embodiments is illustrated. The switch circuit 2880includes a transistor 2882. The transistor 2882 has a base connected tothe output terminal OT of the integrated control module 2860 via thepath 2861, a collector connected to one end of the LED power loop (e.g.,the first installation detection terminal 2521), and an emitterconnected to the detection determining auxiliary circuit. In someembodiments, the transistor 2882 may be replaced by other equivalentlyelectronic parts, e.g., a MOSFET.

It should be noted that, the installation detection module of thepresent embodiment utilizes the same installation detection principle asthe aforementioned embodiment. For example, the capacitor voltage maynot mutate; the voltage of the capacitor in the power loop of the LEDtube lamp before the power loop being conductive is zero and thecapacitor's transient response may appear to have a short-circuitcondition; when the LED tube lamp is correctly installed to the lampsocket, the power loop of the LED tube lamp in transient response mayhave a smaller current-limiting resistance and a bigger peak current;and when the LED tube lamp is incorrectly installed to the lamp socket,the power loop of the LED tube lamp in transient response may have abigger current-limiting resistance and a smaller peak current. Thisembodiment may also meet the UL standard to make the leakage current ofthe LED tube lamp less than 5 MIU. For example, the present embodimentmay determine whether the LED tube lamp is correctly/properly connectedto the lamp socket by detecting the transient response of the peakcurrent. Therefore, the detail operation of the transient current underthe correct installation state and the incorrect installation state maybe seen by referring to the aforementioned embodiment, and it will notbe repeated herein. The following disclosure will focus on describingthe entire circuit operation of the installation detection moduleillustrated in FIG. 15L to 15P.

Referring to FIG. 15L again, when an LED tube lamp is being installed toa lamp socket, the driving voltage may be provided to modules/circuitswithin the installation detection module 2520 when power is provided toat least one end cap of the LED tube lamp. The pulse generatingauxiliary circuit 2840 starts charging in response to the drivingvoltage. The output voltage (referred to “first output voltage”hereinafter) of the pulse generating auxiliary circuit 2840 rises from afirst low level voltage to a voltage level greater than a forwardthreshold voltage after a period (e.g., the period utilized to determinethe cycle of a pulse signal), in which the first output voltage mayoutput to the input terminal of the integrated control module 2860 viathe path 2841. After receiving the first output voltage from the inputterminal IN1, the integrated control module 2860 outputs an enabledcontrol signal (e.g., a high level voltage) to the switch circuit 2880and the pulse generating auxiliary circuit 2840. When the switch circuit2880 receives the enabled control signal, the switch circuit 2880 isturned on so that a power loop of the LED tube lamp is conducted aswell. Herein, at least the first installation detection terminal 2521,the switch circuit 2880, the path 2881, the detection determiningauxiliary circuit 2870 and the second installation detection terminal2522 are included in the power loop. In the meantime, the pulsegenerating auxiliary circuit 2840 conducts a discharge path fordischarging in response to the enabled control signal. The first outputvoltage falls down to the first low level voltage from the voltagegreater than the forward threshold voltage. When the first outputvoltage is less than a reverse threshold voltage (which can be definedbased on the circuit design), the integrated control module 2860 pullsthe enabled control signal down to a disable level in response to thefirst output voltage (i.e., the integrated control module 2860 outputs adisabled control signal, in which the disabled control signal is, forexample, a low level voltage), and thus the control signal has apulse-type signal waveform (i.e., the first time of the first low levelvoltage, the first high level voltage, and the second time of the firstlow level voltage form a first pulse signal DP1). When the power loop isconducting, the detection determining auxiliary circuit 2870 detects afirst sample signal (e.g., voltage signal) on the power loop andprovides the first sample signal to the integrated control module 2860via the input terminal IN2. When the integrated control module 2860determines the first sample signal is greater than or equal to a settingsignal (e.g., a reference voltage), which may represent the LED tubelamp has been properly installed on the lamp socket, the integratedcontrol module 2860 outputs and keeps the enabled control signal to theswitch circuit 2880. Since receiving the enabled control signal, theswitch circuit 2880 remains in the conductive state so that the powerloop of the LED tube lamp is kept on the conductive state as well.During the period when the switch circuit 2880 receives the enabledcontrol signal, the integrated control module 2860 does not output thepulses anymore.

On the contrary, when the integrated control module 2860 determines thefirst sample signal is less than the setting signal, which may representthe LED tube lamp has not been properly installed on the lamp socketyet, the integrated control module 2860 outputs and keeps the disabledcontrol signal to the switch circuit 2880. As a result of receiving thedisabled control signal, the switch circuit 2880 remains in thenon-conducting state so that the power loop of the LED tube lamp is kepton the non-conducting state as well.

Since the discharge path of the pulse generating auxiliary circuit 2840is cut off, the pulse generating auxiliary circuit 2840 starts to chargeagain. Therefore, after the power loop of the LED tube lamp remains in anon-conducting state for a period (i.e., pulse on-time), the firstoutput voltage of the pulse generating auxiliary circuit 2840 rises fromthe first low level voltage to the voltage greater than the forwardthreshold voltage again, in which the first output voltage may output tothe input terminal of the integrated control module 2860 via the path2841. After receiving the first output voltage from the input terminalIN1, the integrated control module 2860 pulls up the control signal fromthe disable level to an enable level (i.e., the integrated controlmodule 2860 outputs the enabled control signal) and provides the enabledcontrol signal to the switch circuit 2880 and the pulse generatingauxiliary circuit 2840. When the switch circuit 2880 receives theenabled control signal, the switch circuit 2880 is turned on so that thepower loop of the LED tube lamp is conducted as well. Herein, at leastthe first installation detection terminal 2521, the switch circuit 2880,the path 2881, the detection determining auxiliary circuit 2870 and thesecond installation detection terminal 2522 are included in the powerloop. In the meantime, the pulse generating auxiliary circuit 2840conducts, in response to the enabled control signal, a discharge pathagain for discharging. The first output voltage gradually falls down tothe first low level voltage from the voltage greater than the forwardthreshold voltage again. When the first output voltage is less than areverse threshold voltage (which can be defined based on the circuitdesign), the integrated control module 2860 pulls the enabled controlsignal down to a disable level in response to the first output voltage(i.e., the integrated control module 2860 outputs a disabled controlsignal, in which the disabled control signal is, for example, a lowlevel voltage), and thus the control signal has a pulse-type signalwaveform (i.e., the third time of the first low level voltage, thesecond time of the high level voltage, and the fourth time of the firstlow level voltage form a second pulse signal DP2). When the power loopis conducted again, the detection determining auxiliary circuit 2870detects a second sample signal (e.g., voltage signal) on the power loopand provides the second sample signal to the integrated control module2860 via the input terminal IN2. When the integrated control module 2860determines the second sample signal is greater than or equal to asetting signal (e.g., a reference voltage), which may represent the LEDtube lamp has been properly installed on the lamp socket, the integratedcontrol module 2860 outputs and keeps the enabled control signal to theswitch circuit 2880. Since receiving the enabled control signal, theswitch circuit 2880 remains in the conductive state so that the powerloop of the LED tube lamp is kept on the conductive state as well.During the period when the switch circuit 2880 receives the enabledcontrol signal, the integrated control module 2860 does not output thepulses anymore.

When the integrated control module 2860 determines the second samplesignal is less than the setting signal, which may represent the LED tubelamp has not been properly installed on the lamp socket yet, theintegrated control module 2860 outputs and keeps the disabled controlsignal to the switch circuit 2880. Since receiving the disabled controlsignal, the switch circuit 2880 remains in the non-conducting state sothat the power loop of the LED tube lamp is kept on the non-conductingstate as well. Based on the above operation, when the LED tube lamp hasnot been properly installed on the lamp socket, the problem in whichusers may get electric shock caused by touching the conductive part ofthe LED tube lamp can be prevented.

Operation of circuits/modules within the installation detection moduleis further described below. Referring to FIG. 15M to 15P, when the LEDtube lamp is installed in the lamp socket, the capacitor 2843 is chargedby a driving voltage VCC via resistor 2842. When the voltage of thecapacitor 2843 is raised to trigger the pulse generating unit 2862(i.e., the voltage of the capacitor 2843 is raised greater than theforward threshold voltage), the output of the pulse generating unit 2862changes to a first high level voltage from an initial first low levelvoltage and provides to the detection result latching unit 2863. Afterreceiving the first high level voltage outputted by the pulse generatingunit 2862, the detection result latching unit 2863 outputs a second highlevel voltage to the base of the transistor 2882 and the resistor 2846via the output terminal OT. After the second high level voltageoutputted from the detection result latching unit 2863 is received bythe base of the transistor 2882, the collector and the emitter of thetransistor are conducted so as to conduct the power loop of the LED tubelamp. Herein, at least the first installation detection terminal 2521,the transistor 2882, the resistor 2872, and the second installationdetection terminal 2522 are included in the power loop.

In the meantime, the base of the transistor 2845 receives the secondhigh level voltage on the output terminal OT via the resistor 2846. Thecollector and the emitter of the transistor 2845 are conducting andconnected to the ground, such that the capacitor 2843 discharges to theground via the resistor 2844. When the voltage of the capacitor 2843 isinsufficient so that the pulse generating unit 2862 cannot be triggered,the output of the pulse generating unit 2862 is pulled down to the firstlow level voltage from the first high level voltage (i.e., the firsttime of the first low level voltage, the first high level voltage, andthe second time of the first low level voltage form a first pulse signalDP1). When the power loop is conducting, the current, generated by thetransient response, passing through a capacitor (e.g., filteringcapacitor in the filtering circuit) in the LED power loop flows throughthe transistor 2882 and the resistor 2872 so as to build a voltagesignal on the resistor 2872. The voltage signal is provided to the inputterminal IN2, and thus the detection unit 2864 may compare the voltagesignal on the input terminal IN2 (i.e., the voltage on the resistor2872) with a reference voltage.

When the detection unit 2864 determines the voltage signal on theresistor 2872 is greater than or equal to the reference voltage, thedetection unit outputs a third high level voltage to the detectionresult latching unit 2863. On the contrary, when the detection unit 2864determines the voltage signal on the resistor 2872 is less than thereference voltage, the detection unit 2864 outputs a third low levelvoltage to the detection result latching unit 2863.

The detection result latching unit 2863 latches/stores the third highlevel voltage/third low level voltage provided by the detection unit2864 and performs a logic operation based on the latched/stored signaland the signal provided by the pulse generating unit 2862, such that thedetection result latching unit 2863 outputs the control signal. Herein,the result of the logic operation determines whether the signal level ofthe outputted control signal is the second high level voltage or thesecond low level voltage.

More specifically, when the detection unit 2864 determines that thevoltage signal on the resistor is greater than or equal to the referencevoltage, the detection result latching unit 2863 may latch the thirdhigh level voltage outputted by the detection unit 2864, and the secondhigh level voltage is maintained to be output to the base of thetransistor 2882, so that the transistor 2882 and the power loop of theLED tube lamp maintain the conductive state. Since the detection resultlatching unit 2863 may continuously output the second high levelvoltage, the transistor 2845 is conducted to the ground as well, so thatthe voltage of the capacitor 2843 cannot rise enough to trigger thepulse generating unit 2862. When the detection unit 2864 determines thatthe voltage signal on the resistor 2872 is less than the referencevoltage, both the detection unit 2864 and the pulse generating unit 2862provide a low level voltage, and thus the detection result latching unit2863 continuously outputs, after performing the OR logical operation,the second low level voltage to the base of the transistor 2882.Therefore, the transistor 2882 is maintained to be cut off and the powerloop of the LED tube lamp is maintained in the non-conducting state.However, since the control signal on the output terminal OT ismaintained at a second low level voltage, the transistor 2845 is thusmaintained in a cut-off state as well, and repeatedly performs the next(pulse) detection until the capacitor 2843 is charged by the drivingvoltage VCC via the resistor 2842 again.

It should be noted that, the detection stage DTS described in thisembodiment can be defined as the period that the driving voltage VCC isprovided to the installation detection module 2520, however, thedetection unit 2864 has not yet determined that the voltage signal onthe resistor 2872 is greater than or equal to the reference voltage.During the detection stage DTS, since the control signal outputted bythe detection result latching unit 2863 alternatively conducts and cutsoff the transistor 2845, the discharge path is periodically conductedand cut off, correspondingly. Thus, the capacitor 2843 is periodicallycharged and discharged in response to the conducting state of thetransistor 2845, so that the detection result latching unit 2863 outputsthe control signal having a periodic pulse waveform during the detectionstage DTS. The detection stage DTS ends when the detection unit 2864determines that the voltage signal on the resistor 2872 is greater thanor equal to the reference voltage or the driving voltage VCC is stopped.The detection result latching unit 2863 is maintained to output thecontrol signal having the second high level voltage or the second lowlevel voltage after the detection stage DTS.

In one embodiment, compared to the exemplary embodiment illustrated inFIG. 15G, the integrated control module 2860 is constituted byintegrating part of the circuit components in the detection pulsegenerating module 2740, the detection result latching circuit 2760, andthe detection determining circuit 2770 (e.g., as part of an integratedcircuit). Another part of the circuit components which are notintegrated in the integrated control module 2860 constitutes the pulsegenerating auxiliary circuit 2840 and the detection determiningauxiliary circuit 2870 of the embodiment illustrated in FIG. 15L. Insome embodiments, the function/circuit configuration of the combinationof the pulse generating unit 2862 in the integrated control module 2860and the pulse generating auxiliary circuit 2840 can be equivalent to thedetection pulse generating module 2740. The function/circuitconfiguration of the detection result latching unit 2863 in theintegrated control module 2860 can be equivalent to the detection resultlatching module 2760. The function/circuit configuration of thecombination of the detection unit 2864 in the integrated control module2860 and the detection determining auxiliary circuit 2870 can beequivalent to the detection determining circuit 2770. However, in theseembodiments, the circuit elements included in the pulse generating unit2862, the detection result latching unit 2863, and the detection unit2864 are included in an integrated circuit (e.g., formed on a die orchip).

Referring to FIG. 15Q, an internal circuit block diagram of athree-terminal switch device according to an exemplary embodiment isillustrated. The installation detection module according to oneembodiment is, for example, a three-terminal switch device 2920including a power terminal VP1, a first switching terminal SP1, and asecond switching terminal SP2. The power terminal VP1 of thethree-terminal switch device 2920 is adapted to receive a drivingvoltage VCC. The first switching terminal SP1 is adapted to connect oneof the first installation detection terminal 2521 and the secondinstallation detection terminal 2522 (the first switching terminal SP1is illustrated as being connected to the first installation detectionterminal 2521 in FIG. 15Q, but the invention is not limited thereto),and the second switching terminal SP2 is adapted to connect to the otherone of the first installation detection terminal 2521 and the secondinstallation detection terminal 2522 (the second switching terminal SP2is illustrated as being connected to the second installation detectionterminal 2522 in FIG. 15Q, but the invention is not limited thereto).

The three-terminal switch device 2920 includes a signal processing unit2930, a signal generating unit 2940, a signal capturing unit 2950, and aswitch unit 2960. In addition, the three-terminal switch device 2920further includes an internal power detection unit 2970. The signalprocessing unit 2930 outputs a control signal having a pulse ormulti-pulse waveform during a detection stage DTS, according to thesignal provided by the signal generating unit 2940 and the signalcapturing unit 2950. The signal processing unit 2930 outputs the controlsignal, in which the signal level of the control signal remains at ahigh level voltage or a low voltage level, after the detection stageDTS, so as to control the conducting state of the switch unit 2960 anddetermine whether to conduct the power loop of the LED tube lamp. Thepulse signal generated by the signal generating unit 2940 can begenerated according to a reference signal received from outside, or byitself, and the present invention is not limited thereto. The term“outside” described in this paragraph is relative to the signalgenerating unit 2940, which means the reference signal is not generatedby the signal generating unit 2940. As such, whether the referencesignal is generated by any of the other circuits within thethree-terminal switch device 2920, or by an external circuit of thethree-terminal switch device 2920, those embodiments belong the scope of“the reference signal received from the outside” as described in thisparagraph. The signal capturing unit 2950 samples an electrical signalpassing through the power loop of the LED tube lamp to generate a samplesignal and detects an installation state of the LED tube lamp accordingto the sample signal, so as to transmit a detection result signal Sdrindicating the detection result to the signal processing unit 2930 forprocessing.

In an exemplary embodiment, the three-terminal switch device 2920 can beimplemented by an integrated circuit. For example, the three-terminalswitch device 2920 can be a three-terminal switch control chip, whichcan be utilized in any type of the LED tube lamp having two end caps forreceiving power so as to provide the function of preventing electricshock. It should be noted that, the three-terminal switch device 2920 isnot limited to merely include three pins/connection terminals. Forexample, a multi-pins switch device (with more than three pins) havingat least three pins having the same configuration and function as theembodiment illustrated in FIG. 15Q can include additional pins for otherpurposes, even though those pins may be not described in detail herein.It should be noted that the various “units” described herein, in someembodiments, are circuits, and will be described as circuits.

In an exemplary embodiment, the signal processing unit 2930, the signalgenerating unit 2940, the signal capturing unit 2950, the switch unit2960, and the internal power detection unit 2970 can be respectivelyimplemented the circuit configurations illustrated in FIG. 15R to 15V,but the present invention is not limited thereto. Detail exemplaryoperation of each of the units in the three-terminal control chip aredescribed below.

Referring to FIG. 15R, a block diagram of a signal processing unitaccording to an exemplary embodiment is illustrated. The signalprocessing unit 2930, which in one embodiment is a circuit, includes adriver 2932, an OR gate 2933, and a D flip-flop 2934. The driver 2932has an input end, and has an output end connected to the switch unit2960 via the path 2931, in which the driver 2932 provides the controlsignal to the switch unit 2960 via the output end and the path 2931. TheOR gate 2933 has a first input end connected to the signal generatingunit 2940 via the path 2941, a second input end, and an output endconnected to the input end of the driver 2932. The D flip-flop 2934 hasa data input end (D) receiving a driving voltage VCC, a clock input end(CK) connected to the signal capturing unit 2950 via the path 2951, andan output connected to the second input terminal of the OR gate 2933.

Referring to FIG. 15S, a block diagram of a signal generating unitaccording to an exemplary embodiment is illustrated. The signalgenerating unit 2940 includes resistors 2942 and 2943, a capacitor 2944,a switch 2945, and a comparator 2946. One end of the resistor 2942receives the driving voltage VCC, and the resistors 2942 and 2943 andthe capacitor 2944 are serial connected between the driving voltage VCCand the ground. The switch 2945 is connected to the capacitor 2944 inparallel. The comparator 2946 has a first input end connected to theconnection node of the resistors 2942 and 2943, a second input endreceives a reference voltage Vref, and an output end connected to thecontrol terminal of the switch 2945.

Referring to FIG. 15T, a block diagram of a signal capturing unitaccording to an exemplary embodiment is illustrated. The signalcapturing unit 2950 includes an OR gate and comparators 2953 and 2954.The OR gate 2952 has a first input end and a second input end, and anoutput end connected to the signal processing unit 2930 via the path2951. The comparator 2953 has a first input end connected to one end ofthe switch unit 2960 (i.e., a node on the power loop of the LED tubelamp) via the path 2962, a second input end receiving a first referencevoltage (e.g., 1.25V, but not limited thereto), and an output endconnected to the first input end of the OR gate 2952. The comparator2954 has a first input end connected to a second reference voltage(e.g., 0.15V, but not limited thereto), a second input end connected tothe first input end of the comparator 2953, and an output end connectedto the second input end of the OR gate 2952.

Referring to FIG. 15U, a block diagram of a switch unit according to anexemplary embodiment is illustrated. The switch unit 2960 includes atransistor 2963. The transistor 2963 has a gate connected to the signalprocessing unit 2930 via the path 2931, a drain connected to the firstswitch terminal SP1 via the path 2961, and a source connected to thesecond switch terminal SP2, the first input end of the comparator 2953,and the second input end of the comparator via the path 2962. In oneembodiment, for example, the transistor 2963 is an NMOS transistor.

Referring to FIG. 15V, a block diagram of an internal power detectionunit according to an exemplary embodiment is illustrated. The internalpower detection unit 2970 includes a clamp circuit 2972, a referencevoltage generating unit 2973, a voltage adjustment circuit 2974, and aSchmitt trigger 2975. The clamp circuit 2972 and the voltage adjustmentcircuit 2974 are respectively connected to the power terminal VP1 forreceiving the driving voltage, so as to perform a voltage clampoperation and a voltage level adjustment operation, respectively. Thereference voltage generating unit 2973 is coupled to the voltageadjustment circuit 2974 and is configured to generate a referencevoltage to the voltage adjustment circuit 2974. The Schmitt trigger 2975has an input end coupled to the clamp circuit 2972 and the voltageadjustment circuit 2974, and an output end to output a powerconfirmation signal for indicating whether the driving voltage VCC isnormally supplied. If the driving voltage VCC is normally supplied, theSchmitt trigger 2975 outputs the enabled power confirmation signal, suchthat the driving voltage VCC is allowed to be provided to thecomponent/circuit within the three-terminal switch device 2920. On thecontrary, if the driving voltage VCC is abnormal, the Schmitt trigger2975 outputs the disabled power confirmation signal, such that thecomponent/circuit within the three-terminal switch device 2920 won't bedamaged based on working under the abnormal driving voltage VCC.

Referring to FIG. 15Q to 15V, under the circuit operation of the presentembodiment, when the LED tube lamp is installed on the lamp socket, thedriving voltage VCC is provided to the three-terminal switch device 2920via the power terminal VP1. At this time, the driving voltage VCCcharges the capacitor 2944 via the resistors 2942 and 2943. When thecapacitor voltage is raised greater than the reference voltage Vref, thecomparator 2946 switches to output a high level voltage to the firstinput end of the OR gate 2933 and the control terminal of the switch2945. The switch 2945 is conducted in response to the received highlevel voltage, such that the capacitor starts to discharge to theground. The comparator 2946 outputs an output signal having pulse-typewaveform through this charge and discharge process.

During the period when the comparator 2946 outputs the high levelvoltage, the OR gate 2952 correspondingly outputs the high level voltageto conduct the transistor 2963, such that the current flows through thepower loop of the LED tube lamp. When the current passes the power loop,a voltage signal corresponding to the current size can be established onthe path 2962. The comparator 2953 samples the voltage signal andcompares the signal level of the voltage signal with the first referencevoltage (e.g., 1.25V).

When the signal level of the sampled voltage signal is greater than thefirst reference voltage, the comparator 2953 outputs the high levelvoltage. The OR gate 2952 generates another high level voltage to theclock input end of the D flip-flop 2934 in response to the high levelvoltage outputted by the comparator 2953. The D flip-flop 2934continuously outputs the high level voltage based on the output of theOR gate 2952. Driver 2932 generates an enabled control signal to conductthe transistor 2963 in response to the high level voltage on the inputterminal. At this time, even if the capacitor 2944 has been dischargedto below the reference voltage Vref and thus the output of thecomparator 2946 is pulled down to the low level voltage, the transistor2963 still remains in the conductive state since the output of the Dflip-flop 2934 is kept on the high level voltage.

When the sampled voltage signal is less than the first reference voltage(e.g., 1.25V), the comparator 2953 outputs the low level voltage. The ORgate 2952 generates another low level voltage in response to the lowlevel voltage outputted by the comparator, and provides the generatedlow level voltage to the clock input end of the D flip-flop 2934. Theoutput end of the D flip-flop 2934 remains on the low level voltagebased on the output of the OR gate 2952. At this time, once thecapacitor 2944 discharges to the capacitor voltage below the referencevoltage Vref, the output of comparator 2946 is pulled down to the lowlevel voltage which represents the end of the pulse on-time (i.e., thefallen edge of the pulse). Since the two input ends of the OR gate 2933are at the low level voltage, the output end of the OR gate 2933 alsooutputs the low level voltage, therefore, the driver 2932 generates thedisabled control signal to cut off the transistor 2963 in response tothe received low level voltage, so as to cut off the power loop of theLED tube lamp.

As noted above, the operation of the signal processing unit 2930 of thepresent embodiment is similar to that of the detection result latchingcircuit 2760 illustrated in FIG. 15I, the operation of the signalgenerating unit 2940 is similar to that of the detection pulsegenerating module 2740 illustrated in FIG. 15H, the operation of thesignal capturing unit 2950 is similar to that of the detectiondetermining circuit 2770 illustrated in FIG. 15K, and the operation ofthe switch unit 2960 is similar to that of the switch circuit 2780illustrated in 15J.

Referring to FIG. 15W, a block diagram of an installation detectionmodule according to an exemplary embodiment is illustrated. Theinstallation detection module 2520 includes a switch circuit 3080, adetection pulse generating module 3040, a control circuit 3060, adetection determining circuit 3070, and a detection path circuit 3090.The detection determining circuit 3070 is coupled to the detection pathcircuit 3090 via the path 3081 for detecting the signal on the detectionpath circuit 3090. The detection determining circuit 3070 is coupled tothe control circuit 3060 via the path 3071 for transmitting thedetection result signal Sdr to the control circuit 3060 via the path3071. The detection pulse generating module 3040 is coupled to thedetection path circuit 3090 via the path 3041 and generates a pulsesignal to inform the detection path circuit 3090 of a time point forconducting the detection path. The control circuit 3060 outputs acontrol signal according to the detection result signal Sdr and iscoupled to the switch circuit 3080 via the path 3061, so as to transmitthe control signal to the switch circuit 3080. The switch circuit 3080determines whether to conduct the current path between the installationdetection terminals 2521 and 2522 (i.e., part of the power loop).

In some embodiments, the detection pulse generating module 3040, thecontrol circuit 3060, the detection determining circuit 3070, and thedetection path circuit 3080 can be referred to a detection circuit or anelectric shock detection/protection circuit, which is configured tocontrol the switching state of the switch circuit 3080.

In the present embodiment, the configuration of the detection pulsegenerating module 3040 can correspond to the configurations of thedetection pulse generating module 2640 shown in FIG. 15C or thedetection pulse generating module 2740 shown in FIG. 15H. Referring toFIG. 15C, when the detection pulse generating module 2640 is applied toimplement the detection pulse generating module 3040, the path 3041 ofthe present embodiment can correspond to the path 2541, which means theOR gate 265 is connected to the detection path circuit 3090 via the path3041. Referring to FIG. 15H, when the detection pulse generating module2740 is applied to implement the detection pulse generating module 3040,the path 3041 can correspond to the path 2741. In one embodiment, thedetection pulse generating module is also connected to the outputterminal of the control circuit 3060 via the path 3061, so that the path3061 can correspond to the path 2761.

The control circuit 3060 can be implemented by a control chip or anycircuit capable of performing signal processing. When the controlcircuit 3060 determines the tube lamp is properly installed (e.g., auser is not touching the pins on one end of the tube lamp with the otherend plugged in) according to the detection result signal Sdr, thecontrol circuit 3060 may control the switch state of the switch circuit3080 so that the external power can be normally provided to the LEDmodule when the tube lamp is properly installed into the lamp socket. Inthis case, the detection path will be cut off by the control circuit3060. On the contrary, when the control circuit 3060 determines the tubelamp is not properly installed (e.g., a user is touching the pins on oneend of the tube lamp with the other end plugged in) according to thedetection result signal Sdr, the control circuit 3060 keeps the switchcircuit 3080 at the off-state since the user has the risk from gettingelectric shock.

In an exemplary embodiment, the control circuit 3060 and the switchcircuit 3080 can be part of the driving circuit in the power supplymodule. For example, if the driving circuit is a switch-type DC-to-DCconverter, the switch circuit 3080 can be the power switch of theconverter, and the control circuit 3060 can be the controller of thepower switch.

An example of the configuration of the detection determining circuit3070 can be seen referring to the configurations of the detectiondetermining circuit 2670 shown in FIG. 15D or the detection determiningcircuit 2770 shown in FIG. 15K. Referring to FIG. 15D, when thedetection determining circuit 2670 is applied to implement the detectiondetermining circuit 3070, the resistor 2672 can be omitted. The path3081 of the present embodiment can correspond to the path 2581, whichmeans the positive input terminal of the comparator 2671 is connected tothe detection path circuit 3090. The path 3071 of the present embodimentcan correspond to the path 2571, which means the output terminal of thecomparator 2671 is connected to the detection result latching circuit3060. Referring to FIG. 15K, when the detection determining circuit 2770is applied to implement the detection determining circuit 3070, theresistor 2774 can be omitted. The path of the present embodiment cancorrespond to the path 2771, which means the output terminal of thecomparators 2772 and 2773 are connected to the detection result latchingcircuit 3060.

The configuration of the switch circuit 3080 can correspond to theconfigurations of the switch circuit 2680 shown in FIG. 15F or theswitch circuit 2780 shown in FIG. 15J. Since the switch circuit in bothembodiments of FIG. 15F and FIG. 15J are similar to each other, thefollowing description discusses the switch circuit 2680 shown in FIG.15F as an example. Referring to FIG. 15F, when the switch circuit 2680is applied to implement the switch circuit 3080, the path 3061 of thepresent embodiment can correspond to the path 2561. The path 2581 is notconnected to the detection determining circuit 2570, but directlyconnected to the installation detection terminal 2522.

An exemplary configuration of the detection path circuit 3090 is shownin FIG. 15X. The detection path circuit 3090 includes a transistor 3092and resistors 3093 and 3094. The transistor 3092 has a base, acollector, and an emitter. The base of the transistor 3092 is connectedto the detection pulse generating module 3040 via the path 3041. Theresistor 3092 is serially connected between the emitter of thetransistor 3092 and the ground. The resistor 3093 is serially connectedbetween the collector of the transistor 3092 and the installationdetection terminal 2521.

In the present embodiment, the transistor 3092 is conducting during apulse-on time when receiving the pulse signal provided by the detectionpulse generating module 3040. Under the situation where at least one endof the tube lamp is inserted in the lamp socket, a detection path isbuilt from the installation detection terminal 2521 to the ground (viathe resistor 3094, the transistor 3092, and the resistor 3093) inresponse to the conducted transistor 3092, so as to establish a voltagesignal on the node X of the detection path. In one embodiment, thedetection path is built from one of the rectifying circuit inputterminals to another one of the rectifying circuit input terminals (viathe rectifying diodes, the resistors 3093 and 3094, and the transistor3092). When the user does not touch the tube lamp (e.g., but one end ofthe tube lamp is plugged in), the signal level of the voltage signal isdetermined by the voltage division of the resistors 3093 and 3094. Whenthe user touches the tube lamp, a human body resistor formed by theresistance of a human body and having an equivalent resistance of ahuman body is connected between the resistor 3094 and the ground, whichmeans it is connected to the resistors 3093 and 3094 in series. At thistime, the signal level of the voltage signal at node X is determined bythe voltage division of the resistor 3093, the resistor 3094, and theimpedance of a human body. The human body resistor refers to anequivalent resistor of a human body. The impedance of the human bodyresistor is usually between 500 ohms and 2000 ohms, depending on theskin humidity. Accordingly, by setting the resistors 3093 and 3094having reasonable resistance, the voltage signal on the node X mayreflect the state of whether the user touches the tube lamp, and thusthe detection determining circuit 3070 may generate the correspondingdetection result signal Sdr according to the voltage signal on the nodeX.

It should be noted that, although the transistor 3092 is illustrated asa BJT for example, the invention is not limited thereto. In someembodiments, the transistor 3092 can be implemented by a MOSFET. Whenutilizing the MOSFET as the transistor 3092, the gate of the transistor3092 is connected to the detection pulse generating module 3040 via thepath 3041. The resistor 3092 is serially connected between the source ofthe transistor 3092 and the ground. The resistor 3093 is seriallyconnected between the drain of the transistor 3092 and the installationdetection terminal 2521.

In addition, although the sample node X is selected from the firstterminal of the transistor 3092 for example, in which the first terminalis the collector terminal if the transistor 3092 is BJT and the firstterminal is the drain terminal if the transistor 3092 is MOSFET, thepresent invention is not limited thereto. The sample node X can beselected from the second terminal of the transistor 3092 as well, inwhich case the second terminal is the emitter terminal if the transistor3092 is BJT and the second terminal is the source terminal if thetransistor 3092 is MOSFET. As a result, the detection determiningcircuit 3070 can detects the signal feature on at least one of the firstterminal and the second terminal of the transistor 3092.

As noted above, the present embodiment may determine whether a user hasa chance to get an electric shock by conducting current in a detectionpath and detecting a voltage signal on the detection path. Compared tothe embodiment mentioned above, the detection path of the presentembodiment is additionally built, but does not use the power loop as thedetection path. In some embodiments, the additional detection pathrefers to at least one electronic element of the detection path circuit3090 being different from electronic elements included in the powerloop. In some embodiments, the additional detection path refers to allof the electronic elements of the detection path circuit 3090 beingdifferent from electronic elements included in the power loop.

Since the configuration of the components on the additional detectionpath is much simpler than the power loop, the voltage signal on thedetection path may reflect a user's touching state more accurately.

Furthermore, similar to the above embodiment, part or all of thecircuit/module can be integrated as a chip, as illustrated in theembodiments in FIG. 15L to FIG. 15V, and it will not be repeated herein.

It should be noted that, the switch circuits 2580, 2680, 2780, 2880,2960 and 3080 mentioned above are embodiments of a current limitingmodule, which is configured to limit the current on the power loop toless than a predetermined value (e.g., 5 MIU) when enabling. Peoplehaving ordinary skill in the art may understand how to implement thecurrent limiting module by circuits operated like a switch according tothe embodiments described above. For example, the current limitingmodule can be implemented by electronic switch (e.g., MOSFET, BJT),electromagnetic switch, relay, triode AC semiconductor switch (TRIAC),Thyristor, impedance variable component (e.g., variable capacitor,variable resistor, variable inductor) and combination of the above.

Further, according to the embodiments illustrated in FIG. 15G to 15X,one skilled in the art should understand that the installation detectionmodule illustrated in FIG. 15G can not only be designed as a distributedcircuit applied in the LED tube lamp, but rather some components of theinstallation detection module can be integrated into an integratedcircuit in an exemplary embodiment (e.g., the embodiment illustrated inFIG. 15L). Alternatively, all circuit components of the installationdetection module can be integrated into an integrated circuit in anotherexemplary embodiment (e.g., the embodiment illustrated in FIG. 15Q).Therefore, the circuit cost and the size of the installation detectionmodule can be saved. In addition, by integrating/modularizing theinstallation detection module, the installation detection module can bemore easily utilized in different types of the LED tube lamps so thatthe design compatibility of the LED tube lamp can be improved. Also,under the application of utilizing the integrated installation detectionmodule in the LED tube lamp, the light emitting area of the LED tubelamp can be significantly improved since the circuit size within thetube lamp is reduced. For example, the integrated circuit design mayreduce the working current (reduced by about 50%) and enhance the powerefficiency of the integrated components. As a result, the saved powercan be used for being supplied to the LED module for emitting light, sothat the luminous efficiency of the LED tube lamp can be furtherimproved.

The embodiments of the installation detection module illustrated in FIG.15B, FIG. 15G, FIG. 15L, FIG. 15Q and FIG. 15W teach the installationdetection module includes a pulse generating mechanism such as thedetection pulse generating modules 2540, 2740, and 3040, the pulsegenerating auxiliary circuit 2840, and the signal generating unit 2940for generating a pulse signal, however, the present invention is notlimited thereto. In an exemplary embodiment, the installation detectionmodule can use the original clock signal in the power supply module toreplace the function of the pulse generating mechanism in the aboveembodiments. For example, in order to generate a lighting control signalhaving a pulse waveform, the driving circuit (e.g., DC-to-DC converter)in the power supply module has a reference clock, originally. Thefunction of the pulse generating mechanism can be implemented by usingthe reference clock of the lighting control signal as a reference, sothat the hardware of the detection pulse generating module 2540, 2740,3040/pulse generating auxiliary module 2840/signal generating unit 2940can be omitted. In this case, the installation detection module canshare the circuit configuration with another part of the circuit in thepower supply module, so as to realize the function of generating thepulse signal. In addition, the duty cycle of the pulse generatingmechanism can be any value in the interval of a real number greater than0 to 1, in which the duty cycle equal to 0 means the power loop isnormally closed, and the duty cycle equal to 1 means the power loop isnormally open.

In some embodiments, when the duty cycle is set to smaller than 1, thedetection operation of the installation detection module is performed bytemporarily conducting a current on the power loop/detection path anddetecting a signal on the power loop/detection path to obtain theinstallation state of the LED tube lamp without causing electric shock.When the LED tube lamp is correctly installed on the lamp socket (i.e.,the pins on the both end caps are correctly connected to the connectingsockets), the current limiting module is disabled for conducting thedriving current on the power loop, so as to drive/light up the LEDmodule. Under such configuration, the current limiting module is presetto be in an enable state, so that the power loop can be maintained inthe non-conducting state before confirming whether there is the risk ofelectric shock (or whether the LED tube lamp is correctly installed).The current limiting module is switched to a disable state when the LEDtube lamp is correctly installed. Taking the switch circuit for example,the enable state of the current limiting module refers to the switchcircuit being cut-off, and the disable state of the current limitingmodule refers to the switch circuit being turned on. Such configurationcan be referred to as a pulse detection setting (the duty cycle isgreater than 0 and smaller than 1). Under the pulse detection setting,the installation detection means performs during the pulse-on time ofeach pulse after powering up, and the electric shock protection means isimplemented by suspending the current flowing through the power loopuntil the correct installation state is detected or the risk of electricshock is excluded.

In some embodiments, when the duty cycle is set to equal to 1, thedetection operation of the installation detection module is performed bycontinuously monitoring/sampling the signal on the power loop/detectionpath. The sample signal can be used for determining the equivalentimpedance of the power loop/detection path. When the equivalentimpedance indicates there is a risk of electric shock (i.e., a usertouches the conductive part of the LED tube lamp), the current limitingmodule is switched to be in the enable state for cutting off the powerloop. Under such configuration, the current limiting module is preset tobe in the disable state, so that the power loop can be maintained in theconducting/non-limiting state before confirming whether there is therisk of electric shock (or whether the LED tube lamp is correctlyinstalled), in which case the LED tube lamp can be lighted up in thepreset condition. The current limiting module is switched to the enablestate when the risk of electric shock is detected. Such configurationcan be referred to a continuous detection setting (the duty cycle equalsto 1). Under the continuous detection setting, the installationdetection means performs continuously without considering whether theLED tube lamp is lighted up or not, after powering up, and the electricshock protection means is implemented by allowing the current to flowthrough the power loop until the incorrect installation state or therisk of electric shock is detected. Either the incorrect installationstate or the risk of electric shock being detected can be referred to anabnormal state.

Specifically, as shown in FIG. 15Y, the risk of electric shock may occuras long as one end of the LED tube lamp is connected to the externalpower. Therefore, no matter whether installing or removing the LED tubelamp, once the user touches the conductive part of the tube lamp, theuser is exposed to the risk of electric shock. In order to avoid therisk of electric shock, no matter whether the LED tube lamp is lightedup or not, the installation detection module operates based on the pulsedetection setting or the continuous detection setting to detect theinstallation state and the user touching state and protect the user frombeing electrically shocked. Therefore, the safety of the LED tube lampcan be further improved.

Under the continuous detection setting, the pulse generating mechanismcan be referred to as a path enabling mechanism, which is configured toprovide a conduction signal for turning on the power loop/detectionpath. In some embodiments, for circuit structures of the detection pulsegenerating modules 2540, 2740 and 3040, the pulse generating auxiliarymodule 2840 and signal generating unit 2940 can be correspondinglymodified to a circuit for providing fixed voltage. In addition, theswitch circuits 2580, 2680, 2780, 2880, 2960 and 3080 can be modified tobe preset to be in the conducting state/turn-on state, and to switch tothe non-conducting state/cut-off state when the risk of electric shockis detected (it can be implemented by modifying the logic gate of thedetection result latching circuit). In some embodiments, the circuit forgenerating a pulse can be omitted by modifying the circuit structure ofthe detection determining circuit and the detection path circuit. Forexample, under the continuous detection setting, the detection pulsegenerating module 2540 in the installation detection module of FIG. 15Band the detection pulse generating module 2740 in the installationdetection module of FIG. 15G can be omitted, and so on. In addition,according to the embodiment of disposing the additional detection pathin the installation detection module, the detection pulse generatingmodule 3040 can be omitted if the continuous detection setting isapplied, and the detection path circuit 3090 is maintained in theconducting state (e.g., the transistor 3092 is omitted).

FIG. 16A is a block diagram of an exemplary power supply module in anLED tube lamp according to some exemplary embodiments. Referring to FIG.16A, the LED tube lamp includes a rectifying circuit 510, a filteringcircuit 520 and a driving circuit 2530. Compared with the embodiment ofFIG. 12A, the LED tube lamp of the present embodiment further includes adetection circuit 2620. The connection between the rectifying circuit510, the filtering circuit 520, the driving circuit 2530 and the LEDmodule 630 are similar to the embodiment illustrated in FIG. 12A, andthus is not described in detail herein. The detection circuit 2620 hasan input terminal coupled to the power loop of the LED tube lamp and anoutput terminal coupled to the driving circuit 2530.

Specifically, after the LED tube lamp is powered up (no matter whetheror not the LED tube lamp is correctly installed on the lamp socket), thedriving circuit 2530 enters an installation detection mode. Under theinstallation detection mode, the driving circuit 2530 provides alighting control signal having narrow pulse (e.g., the pulse-on time issmaller than 1 ms) for driving the power switch (not shown), so that thedriving current, generated under the installation detection mode, issmaller than 5 MIU or 5 mA. On the other hand, under the installationdetection mode, the detection circuit 2620 detects an electrical signalon the power loop/detection path and generates an installation detectionsignal Sidm, in which the installation detection signal Sidm istransmitted to the driving circuit. The driving circuit 2530 determineswhether to enter a normal driving mode according to the receivedinstallation detection signal Sidm. If the driving circuit 2530determines to maintain in the installation detection mode, which meansthe LED tube lamp is not correctly installed on the lamp socket duringthe first pulse, the next pulse is output, according to a frequencysetting, for temporarily conducting the power loop/detection path, sothat the electrical signal on the power loop/detection path can bedetected by the detection circuit 2620 again. On the contrary, if thedriving circuit 2530 determines to enter the normal driving mode, thedriving circuit 2530 generates, according to at least one of the inputvoltage, the output voltage, the input current, the output current andthe combination of the above, the lighting control signal capable ofmodulating the pulse width for maintaining the brightness of the LEDmodule 630. In the present embodiment, the input/output voltage and theinput/output current can be sampled by a feedback circuit (not shown) inthe driving circuit 2530.

FIG. 16B is a schematic diagram of an exemplary driving circuitaccording to some exemplary embodiments. Referring to FIG. 16B, thedriving circuit 2530 includes a controller 2531 and a conversion circuit2532. The controller 2531 includes a signal receiving unit 2533, asawtooth wave generating unit 2534 and a comparison unit 2536, and theconversion circuit 2532 includes a switch circuit (also known as powerswitch) 2535 and energy release circuit 2538. The signal receiving unit2533 has input terminals for receiving a feedback signal Vfb andinstallation detection signal Sidm and an output terminal coupled to afirst input terminal of the comparison unit 2536. The sawtooth wavegenerating unit 2534 has an output terminal coupled to a second inputterminal of the comparison unit 2536. An output terminal of thecomparison unit 2536 is coupled to a control terminal of the switchcircuit 2535. The circuit arrangement of the switch circuit 2535 and theenergy release circuit 2538 can be referred to with respect to theembodiments of FIGS. 12A, 12B, 12G-12J, and it will not be repeatedherein.

In the controller 2531, the signal receiving unit 2533 can beimplemented by, for example, a circuit constituted by an erroramplifier. The error amplifier is configured to receive the feedbacksignal Vfb related to the voltage/current information of the powersupply module and the installation detection module Sidm. In the presentembodiment, the signal receiving unit 2533 selectively outputs a presetvoltage Vp or the feedback signal Vfb to the first input terminal of thecomparison unit 2536. The sawtooth wave generating unit 2534 isconfigured to generate and provide a sawtooth signal Ssw to the secondinput terminal of the comparison unit 2536. In the waveform of thesawtooth signal Ssw of each cycle, the slope of at least one of therising edge and the falling edge is not infinity. In some embodiments,the sawtooth wave generating unit 2534 generates the sawtooth signalSsw, according to a fixed operation frequency, no matter what theoperation mode of the driving circuit 2530 is. In some embodiments, thesawtooth wave generating unit 2534 generates the sawtooth signal Sswaccording to different operation frequencies when operating in differentoperation modes. For example, the sawtooth wave generating unit 2534 canchange the operation frequency according to the installation detectionsignal Sidm. The comparison unit 2536 compares the signal level of thesignal on the first and the second input terminal, in which thecomparison unit 2536 outputs the lighting control signal Slc with highvoltage level when the signal level on the first input terminal isgreater than the second input terminal and outputs the lighting controlsignal Slc with low voltage level when the signal level on the firstinput terminal is not greater than the second input terminal. Forexample, the comparison unit 2536 outputs high voltage when the signallevel of the sawtooth signal Ssw is greater than the preset voltage Vpor the feedback signal Vfb, so as to generate the lighting controlsignal having pulse waveform.

FIG. 17C is a signal waveform diagram of an exemplary power supplymodule according to an exemplary embodiment. Referring to FIGS. 16B and17C, when the LED tube lamp is powered up (including the pins on theboth end caps being connected to the connecting sockets, or the pins onone end cap being connected to the corresponding connecting socket andthe pins on the other end cap being touched by the user), the drivingcircuit 2530 starts to operate and enter the installation detection modeDTM. The operation in the first period T1 is described below. Under theinstallation detection mode, the signal receiving unit 2533 outputs thepreset voltage Vp to the first input terminal of the comparison unit2536, and the sawtooth wave generating unit 2534 provides the sawtoothsignal SW to the second input terminal of the comparison unit 2536. Fromthe perspective of the variation of the sawtooth wave SW, the signallevel of the sawtooth wave SW gradually increases, after the starttimepoint ts, from the initial level to a peak level. After reaching thepeak level, the sawtooth wave SW is gradually decreased to the initiallevel. Before the signal level of the sawtooth wave SW rises to thepreset voltage Vp, the comparison unit 2536 outputs the lighting controlsignal Slc with low voltage. During the period from the timepoint of thesignal level rising to exceed the preset voltage Vp to the timepointfalling back below the preset voltage Vp, the comparison unit 2536 pullsthe signal level up to the high voltage. After the signal level fallingto lower than the preset voltage Vp, the comparison unit 2536 pulls thesignal level down to the low voltage again. By performing the aboveoperation, the comparison unit 2536 can generate the pulse DP based onthe sawtooth wave SW and the preset voltage Vp, in which the pulsewidth/pulse-on time DPW of the pulse DP is the duration that the signallevel of the sawtooth wave SW is higher than the preset voltage Vp.

The lighting control signal Slc having the pulse DP is transmitted tothe control terminal of the switch circuit 2535, so that the switchcircuit 2535 is turned on during the pulse-on time DPW. Therefore, theenergy release unit 2538 absorbs power and a current is generated on thepower loop/detection path in response to the switch circuit being turnedon. Since the current generated on the power loop/detection path leadsto a signal feature, such as signal level, waveform, and/or frequencychanging, the signal feature variation of the sample signal Ssp will bedetected by the detection circuit 2620. In the present embodiment, thedetection circuit 2620 detects the voltage for example, but theinvention is not limited thereto. Under the first period T1, since thevoltage variation SP does not exceed the reference voltage Vref, thedetection circuit 2620 output the corresponding installation detectionsignal Sidm to the signal receiving unit 2533, so that the signalreceiving unit 2533 is maintained in the installation detection mode DTMand continuously outputs the preset voltage Vp to the comparison unit2536. Since the voltage variation of the sample signal Ssp under thesecond period T2 is similar to the sample signal Ssp under the firstperiod T1, the circuit operation under the first and the second periodsT1 and T2 are similar, so that the detailed description is not repeatedherein.

Conclusively, under the first and the second periods T1 and T2, the LEDtube lamp is determined to be not correctly installed. In addition,during the first and the second periods T1 and T2, although the drivingcircuit 2530 generates the driving current on the power loop, thecurrent value of the driving current does not cause electric shock tothe human body because of the turn-on time of the switch circuit 2535 isrelatively short, in which the current value is smaller than 5 MIU/mAand can be reduced to 0.

After entering the third period T3, the detection circuit 2620determines the voltage variation of the sample signal Ssp exceeds thereference voltage Vref, so as to provide the corresponding installationdetection signal Sidm, indicating the LED tube lamp is correctlyinstalled, to the signal receiving unit 2533. When the signal receivingunit 2533 receives the installation detection signal Sidm indicating thecorrect installation state, the driving circuit 2530 enters, after theend of the third period T3, the normal driving mode DRM from theinstallation detection mode DTM. Under the fourth period T4 of thenormal driving mode DRM, the signal receiving unit 2533 generates thecorresponding signal to the comparison unit 2536 according to thefeedback signal Vfb instead of the preset voltage Vp, so that thecomparison unit 2536 is capable of dynamically modulating the pulse-ontime of the lighting control signal Slc according to the drivinginformation such as the input voltage, the output voltage and/or thedriving current. From the perspective of the signal waveform of thelighting control signal Sc, since the pulse DP is configured to detectthe installation state/risk of electric shock, the pulse width of thepulse DP is relatively narrow, compared to the pulse width under thenormal driving mode DRM. For example, the pulse width of the pulse underthe installation detection mode DTM (e.g., DP) is less than the minimumpulse width under the normal driving mode DRM.

In some embodiments, the detection circuit 2620 stops operating underthe normal driving mode DRM. In some embodiments, under the normaldriving mode DRM, the signal receiving unit 2533 ignores theinstallation detection signal Sidm regardless of whether the detectioncircuit 2620 continuously operates.

In summary, comparing the power supply module illustrated in FIGS. 16Aand 16B to the power supply module described above, one difference isthat circuits for implementing the installation detection function andthe electric shock protection function are integrated into the drivingcircuit, so that the driving circuit becomes the driving circuit havingthe installation detection function and the electric shock protectionfunction. Specifically, for the circuit structure, only an additionaldetection circuit (2620), for detecting the electrical signal on thepower loop/detection path, is used to implement the installationdetection function and the electric shock protection function with thedriving circuit 2530. Since the detection pulse generating module, thedetection result latching circuit, the detection determining circuit andthe switch circuit are not required, the cost of the overall powersupply module can be effectively reduced. In addition, since the circuitcomponents/elements are reduced, the power supply module may have morearea for layout and the power consumption can be reduced. The savedpower can be used for driving the LED module so as to enhance theluminous efficiency, and the heat caused by the power supply module canbe reduced as well.

FIG. 16C is a block diagram of an exemplary power supply module in anLED tube lamp according to some exemplary embodiments. Referring to FIG.16C, the installation detection module 2720 has a circuit configurationfor continuously detecting the signal on the power loop. Theinstallation detection module 2720 includes the control circuit 3160,the detection determining circuit 3170 and the current limiting circuit3180. The control circuit 3160 is configured to control the currentlimiting circuit 3180 according to the detection result generated by thedetection determining circuit 3170, so that the current limiting circuit3180 determines whether to perform the current limiting operation, forlimiting the current on the power loop, based on the control of thecontrol circuit 3160. In the present embodiment, the control circuit3160 is preset to not perform the current limiting operation, whichmeans the current on the power loop is not limited by the currentlimiting circuit 3180 at the preset state. Therefore, under the presetstate, as long as the external AC power source is connected to the LEDtube lamp, the input power can be provided to the LED module 630 throughthe power loop.

The following description describes the operation of detecting thesignal on the power loop for example, but the invention is not limitedthereto. In detail, when the external AC power source connects to theLED tube lamp, the input power enables the detection determining circuit3170 for starting to detect the signal on a specific node of the powerloop, and the detection result is transmitted to the control circuit3160. The control circuit 3160 determines whether the conductive part istouched by a user according to at least one signal feature, such as thevoltage/current level, the waveform, the frequency and other features,of the detection result signal. When the control circuit 3160 determinesthe LED tube lamp is touched by a user according to the detection resultsignal, the control circuit 3160 controls the current limiting circuit3180 to perform the current limiting operation, so that the current onthe power loop is limited to lower than a predetermined value, andtherefore the occurrence of electric shock can be prevented/avoided.

FIG. 16D is a block diagram of an exemplary power supply module in anLED tube lamp according to some exemplary embodiments. Referring to FIG.16D, the installation detection module 2820 of the present embodiment issubstantially the same as the installation detection module 2720. Thedifference is the installation detection module 2820 has a circuitconfiguration for continuously detecting the signal on the detectionpath. The installation detection module 2820 includes a control circuit3260, a detection determining circuit 3270, a current limiting circuit3280 and a detection path circuit 3290. The operation of the controlcircuit 3260, detection determining circuit 3270 and the currentlimiting circuit 3280 can be referred to in connection with theembodiments of FIG. 16C, and it will not be repeated herein.

The detection path circuit 3290 can be disposed on the input side or theoutput side of one of the rectifying circuit 510, the filtering circuit520, the driving circuit 1530 and the LED module 630, and the presentinvention is not limited thereto. In addition, in the practicalapplication, the detection path circuit 3290 can be implemented by anycircuit structure capable of responding the impedance variation causedby the human body. For example, the detection path circuit 3290 can beformed by at least one passive component (e.g., resistor, capacitor,inductor), at least one active component (e.g., MOSFET, siliconcontrolled rectifier (SCR)) or the combination of the above.

In summary, the power supply modules illustrated in FIGS. 16C and 16Dare configured in a continuous detection setting, which refers to thepower supply module having a circuit (e.g., the installation detectionmodule 2720/2820) for continuously detecting the installation state orthe risk of electric shock. In some embodiments, under the continuousdetection setting, the power loop/detection path is preset to be in aconducting state or a non-limiting state, and the current on the powerloop would not be limited until the incorrect installation state or therisk of electric shock (the LED tube lamp is touched by a user) isdetected.

Some embodiments of the power supply module illustrated in FIGS. 15A to15X are configured in a pulse detection setting, which refers to thepower supply module having a circuit (e.g., the installation detectionmodule 2520 and the detection circuit 2620) for detecting theinstallation state or the risk of electric shock in certain duration(e.g., the pulse-on time). For example, under the pulse detectionsetting, the power loop/detection path is preset to be in anon-conducting state or a current limiting state. Before confirming theinstallation state or the risk of electric shock, the powerloop/detection path is only turned on when the pulse-on time occurs. Inaddition, the current on the power would be limited until the correctinstallation state or no risk of electric shock (the LED tube lamp isnot touched by a user) is detected. From the perspective of the currentlimiting circuit such as the switch circuit 2580, 2780, 2880, 2960 or3080, the current limiting circuit being disabled refers to the currentlimiting circuit not limiting the current on the power loop, whichcauses the power loop to be in the conducting state or the non-limitingstate. On the other hand, the current limiting circuit being enabledrefers to the current limiting circuit limiting the current on the powerloop, which causes the power loop to be in the non-conducting state orthe current limiting state.

In some embodiments, the continuous detection setting can beindependently used for implementing the installation detection and theelectric shock protection mechanism.

In some embodiments, the continuous detection setting and the pulsedetection setting can be used together for implementing the installationdetection and the electric shock protection mechanism. For example, theLED tube lamp can utilize the pulse detection setting before the LEDmodule is lighted up and can then change to the continuous detectionsetting during the LED tube lamp emitting light.

From the perspective of the circuit operation, the switching of thepulse detection setting and the continuous detection setting can bedetermined based on the current on the power loop. For example, when thecurrent on the power loop is smaller than the predetermined value (e.g.,5 MIU), the installation detection module enables the pulse detectionsetting. If the current on the power loop is detected to be greater thanthe predetermined value, the installation detection module changes toenable the continuous detection setting. From the perspective of theoperation and the installation of the LED tube lamp, the installationdetection module is preset to enable the pulse detection setting, sothat the installation detection module utilizes the pulse detectionsetting for detecting the installation state (or the risk of electricshock) and performing the electric shock protection when the LED tubelamp is powered up. As long as the correct installation state isdetected, the installation detection module changes to utilize thecontinuous detection setting for detecting whether the conductive partof the LED tube lamp is touched by a user during the LED tube lampemitting light. In addition, the installation detection module will bereset to the pulse detection setting if the LED tube lamp is poweredoff.

Although the modules/circuits are named by their functionality in theembodiments described in the present disclosure, it should be understoodby those skilled in the art that the same circuit component may beconsidered to have different functions based on the circuit design. Thatis, different modules/circuits may share the same circuit component toimplement their respective circuit functions. Thus, the functionalnaming of the present disclosure is not intended to limit a particularunit, circuit, or module to particular circuit components.

To summarize, the embodiments illustrated in FIG. 15A to FIG. 15X teacha concept of electric shock protection by utilizing electrical controland detection method. Compared to mechanical electric shock protection(i.e., using the mechanical structure interaction/shifting forimplementing the electric shock protection), the electrical electricshock protection has higher reliability and durability since themechanical fatigue issue may not occur in the electrical installationdetection module.

In some embodiments, the power supply module can be divided into twosub-modules, in which the two sub-modules are respectively disposed inthe different end caps and the sum of power of the sub-modules equals tothe predetermined output power of the power supply module.

According to some embodiments, the present invention further provides adetection method adopted by a light-emitting device (LED) tube lamp forpreventing a user from electric shock when the LED tube lamp is beinginstalled on a lamp socket. The detection method includes: generating afirst pulse signal by a detection pulse generating module, wherein thedetection pulse generating module is configured in the LED tube lamp;receiving the first pulse signal through a detection result latchingcircuit by a switch circuit, and making the switch circuit conductingduring the first pulse signal to cause a power loop of the LED tube lampto be conducting, wherein the switch circuit is on the power loop; anddetecting a first sample signal on the power loop by a detectiondetermining circuit as the power loop being conductive, and comparingthe first sample signal with a predefined signal, wherein when the firstsample signal is greater than or equal to the predefined signal, thedetection method further includes: outputting a first high level signalby the detection determining circuit; receiving the first high levelsignal by the detection result latching circuit and outputting a secondhigh level signal; and receiving the second high level signal by theswitch circuit and conducting to cause the power loop to remainconductive.

In some embodiments, when the first sample signal is smaller than thepredefined signal, the detection method further includes: outputting afirst low level signal by the detection determining circuit; receivingthe first low level signal by the detection result latching circuit andoutputting a second low level signal; and receiving the second low levelsignal by the switch circuit and maintaining an off state of the switchcircuit to cause the power loop to remain open.

In some embodiments, when the power loop remains open, the detectionmethod further includes: generating a second pulse signal by thedetection pulse generating module; receiving the second pulse signalthrough the detection result latching circuit by the switch circuit, andchanging an off state of the switch circuit to a conducting state againduring the second pulse signal to cause the power loop to be conductingonce more; and detecting a second sample signal on the power loop by thedetection determining circuit as the power loop being conductive oncemore, and comparing the second sample signal with the predefined signal,wherein when the second sample signal is greater than or equal to thepredefined signal, the detection method further includes: outputting thefirst high level signal by the detection determining circuit; receivingthe first high level signal by the detection result latching circuit andoutputting the second high level signal; and receiving the second highlevel signal by the switch circuit and maintaining a conducting state ofthe switch circuit to cause the power loop to remain conducting.

In some embodiments, when the second sample signal is smaller than thepredefined signal, the detection method further includes: outputting thefirst low level signal by the detection determining circuit; receivingthe first low level signal by the detection result latching circuit andoutputting the second low level signal; and receiving the second lowlevel signal by the switch circuit and maintaining an off state of theswitch circuit to cause the power loop to remain open.

In some embodiments, a period (or a width) of the first pulse signal isbetween 10 microseconds-1 millisecond, a period (or a width) of thesecond pulse signal is between 10 microseconds-1 millisecond.

In some embodiments, a time interval between the first and the secondpulse signals (or a cycle of the pulse signal) includes (X+Y)(T/2),where T is the cycle of the driving signal, X is an integer which isbigger than or equal to zero, 0<Y<1.

In some embodiments, a period (or a width) of the first pulse signal isbetween 1 microsecond-100 microseconds, a period (or a width) of thesecond pulse signal is between 1 microsecond-100 microseconds.

In some embodiments, a time interval between the first and the secondpulse signals (or a cycle of the pulse signal) is between 3milliseconds-500 milliseconds.

In some embodiments, a protection device is electrically connectedbetween the power supply module and the pins on the end caps. Forexample, a rated current fuse or a resistance type fuse (e.g., picofuse) may be used.

In some embodiments, at least two protection elements, such as twofuses, are respectively connected between the internal circuits of theLED tube lamp and the conductive pins of the LED tube lamp, and whichare on the power loop of the LED tube lamp. In some embodiments, fourfuses are used for an LED tube lamp having power-supplied at its bothend caps respectively having two conductive pins. In this case, forexample, two fuses are respectively connected between two conductivepins of one end cap and between one of the two conductive pins of thisend cap and the internal circuits of the LED tube lamp; and the othertwo fuses are respectively connected between two conductive pins of theother end cap and between one of the two conductive pins of the otherend cap and the internal circuits of the LED tube lamp. In someembodiment, the capacitance between a power supply (or an externaldriving source) and the rectifying circuit of the LED tube lamp may beranging from 0 to about 100 pF. In some embodiments, the abovementionedinstallation detection module may be configured to use an external powersupply.

According to the design of the power supply module, the external drivingsignal may be a low frequency AC signal (e.g., commercial power), a highfrequency AC signal (e.g., that provided by an electronic ballast), or aDC signal (e.g., that provided by a battery or external configureddriving source), input into the LED tube lamp through a drivearchitecture of dual-end power supply. For the drive architecture ofdual-end power supply, the external driving signal may be input by usingonly one end thereof as single-end power supply.

The LED tube lamp may omit the rectifying circuit in the power supplymodule when the external driving signal is a DC signal.

According to the design of the rectifying circuit in the power supplymodule, there may be a dual rectifying circuit. First and secondrectifying circuits of the dual rectifying circuit are respectivelycoupled to the two end caps disposed on two ends of the LED tube lamp.The dual rectifying circuit is applicable to the drive architecture ofdual-end power supply. Furthermore, the LED tube lamp having at leastone rectifying circuit is applicable to the drive architecture of a lowfrequency AC signal, high frequency AC signal or DC signal.

The dual rectifying circuit may comprise, for example, two half-waverectifier circuits, two full-wave bridge rectifying circuits or onehalf-wave rectifier circuit and one full-wave bridge rectifying circuit.

According to the design of the pin in the LED tube lamp, there may betwo pins in single end (the other end has no pin), two pins incorresponding ends of two ends, or four pins in corresponding ends oftwo ends. The designs of two pins in single end and two pins incorresponding ends of two ends are applicable to a signal rectifyingcircuit design of the rectifying circuit. The design of four pins incorresponding ends of two ends is applicable to a dual rectifyingcircuit design of the rectifying circuit, and the external drivingsignal can be received by two pins in only one end or any pin in each oftwo ends.

According to the design of the filtering circuit of the power supplymodule, there may be a single capacitor, or π filter circuit. Thefiltering circuit filers the high frequency component of the rectifiedsignal for providing a DC signal with a low ripple voltage as thefiltered signal. The filtering circuit also further comprises the LCfiltering circuit having a high impedance for a specific frequency forconforming to current limitations in specific frequencies of the ULstandard. Moreover, the filtering circuit according to some embodimentsfurther comprises a filtering unit coupled between a rectifying circuitand the pin(s) for reducing the EMI resulted from the circuit(s) of theLED tube lamp. The LED tube lamp may omit the filtering circuit in thepower supply module when the external driving signal is a DC signal.

According to the design of the LED lighting module in some embodiments,the LED lighting module may comprise the LED module and the drivingcircuit or only the LED module. The LED module may be connected with avoltage stabilization circuit in parallel for preventing the LED modulefrom over voltage. The voltage stabilization circuit may be a voltageclamping circuit, such as Zener diode, DIAC and so on. When therectifying circuit has a capacitive circuit, in some embodiments, twocapacitors are respectively coupled between two corresponding pins intwo end caps and so the two capacitors and the capacitive circuit as avoltage stabilization circuit perform a capacitive voltage divider.

If there are only the LED module in the LED lighting module and theexternal driving signal is a high frequency AC signal, a capacitivecircuit (e.g., having at least one capacitor) is in at least onerectifying circuit and the capacitive circuit is connected in serieswith a half-wave rectifier circuit or a full-wave bridge rectifyingcircuit of the rectifying circuit and serves as a current modulationcircuit (or a current regulator) to modulate or to regulate the currentof the LED module due to that the capacitor equates a resistor for ahigh frequency signal. Thereby, even different ballasts provide highfrequency signals with different voltage logic levels, the current ofthe LED module can be modulated into a defined current range forpreventing overcurrent. In addition, an energy-releasing circuit isconnected in parallel with the LED module. When the external drivingsignal is no longer supplied, the energy-releasing circuit releases theenergy stored in the filtering circuit to lower a resonance effect ofthe filtering circuit and other circuits for restraining the flicker ofthe LED module. In some embodiments, if there are the LED module and thedriving circuit in the LED lighting module, the driving circuit may be abuck converter, a boost converter, or a buck-boost converter. Thedriving circuit stabilizes the current of the LED module at a definedcurrent value, and the defined current value may be modulated based onthe external driving signal. For example, the defined current value maybe increased with the increasing of the logic level of the externaldriving signal and reduced with the reducing of the logic level of theexternal driving signal. Moreover, a mode switching circuit may be addedbetween the LED module and the driving circuit for switching the currentfrom the filtering circuit directly or through the driving circuitinputting into the LED module.

A protection circuit may be additionally added to protect the LEDmodule. The protection circuit detects the current and/or the voltage ofthe LED module to determine whether to enable corresponding over currentand/or over voltage protection.

According to the design of the auxiliary power module of the powersupply module, the energy storage unit may be a battery (e.g., lithiumbattery, graphene battery) or a supercapacitor, connected in parallelwith the LED module. The auxiliary power module is applicable to the LEDlighting module having the driving circuit.

According to the design of the LED module of the power supply module,the LED module comprises plural strings of LEDs connected in parallelwith each other, wherein each LED may have a single LED chip or pluralLED chips emitting different spectrums. Each LEDs in different LEDstrings may be connected with each other to form a mesh connection.

In other words, the abovementioned features can be implemented in anycombination to improve the LED tube lamp.

The above-mentioned exemplary features of the present invention can beaccomplished in any combination to improve the LED tube lamp, and theabove embodiments are described by way of example only. The presentinvention is not herein limited, and many variations are possiblewithout departing from the spirit of the present invention and the scopeas defined in the appended claims.

What is claimed is:
 1. A ballast by-pass light-emitting diode (LED) tubelamp having at least a first and second external connection terminaleach connected to an opposite side of the ballast by-pass LED tube lamp,comprising: a driving circuit, electrically connected to the first andsecond external connection terminals for receiving an external drivingsignal and configured to convert the external driving signal into a lampdriving signal, wherein the external driving signal has a frequencysubstantially equal to 50 Hz or 60 Hz; an LED module, electricallyconnected to the driving circuit, for receiving the lamp driving signal;a current limiting circuit, electrically connected between the at leastone of the first and second external connection terminals and the LEDmodule, and configured to limit a current flowing through the externalconnection terminals and the LED module to less than a predeterminedvalue when being enabled and conduct a current above the predeterminedvalue when being disabled; and an electric shock detection circuit,configured to temporarily turn on a detection path of the ballastby-pass LED tube lamp for 10 μs to 30 μs and detect an equivalentimpedance of the detection path being turned on, wherein the electricshock detection circuit controls the enable/disable state of the currentlimiting circuit according to the equivalent impedance.
 2. The ballastby-pass LED tube lamp according to claim 1, wherein when the equivalentimpedance is greater than a reference value, the electric shockdetection circuit determines a risk of electric shock is detected andenables the current limiting circuit.
 3. The ballast by-pass LED tubelamp according to claim 1, wherein when the equivalent impedance islesser than a reference value, the electric shock detection circuitdetermines the risk of electric shock is not detected and disables thecurrent limiting circuit.
 4. The ballast by-pass LED tube lamp accordingto claim 1, wherein a current path is formed between the externalconnection terminals and the LED module, and the electric shockdetection circuit comprises: a transistor, having a first terminal, asecond terminal, and a control terminal receiving a pulse signal; afirst resistor, electrically connected between the current path and thefirst terminal of the transistor; and a second resistor, electricallyconnected between the second terminal of the transistor and a ground,wherein the transistor, the first resistor, and the second resistorforms the detection path.
 5. The ballast by-pass LED tube lamp accordingto claim 4, wherein when the risk of electric shock is not detected, theequivalent impedance is equal to a summation of the resistance of thetransistor, the first resistor and the second resistor.
 6. The ballastby-pass LED tube lamp according to claim 4, wherein when the risk ofelectric shock is detected, a resistance equivalent to a human bodyresistor is connected to the transistor, the first resistor, and thesecond resistor in series, and the equivalent impedance equals to asummation of the resistance of the transistor, the first resistor, thesecond resistor and the resistance equivalent to the human bodyresistor.
 7. The ballast by-pass LED tube lamp according to claim 1,wherein the entire detection path is part of a current path between thefirst and second external connection terminals and including the LEDmodule.
 8. The ballast by-pass LED tube lamp according to claim 1,wherein the driving circuit comprises: a constant current controller,configured to generate a lighting control signal having a pulsewaveform; a power switch, electrically connected to the constant currentcontroller and configured to be switched according to the lightingcontrol signal; and a conversion circuit, electrically connected to thepower switch and configured to absorb and release power in response tothe switching state of the power switch so as to generate the lampdriving signal.
 9. The ballast by-pass LED tube lamp according to claim8, wherein the current limiting circuit is integrated into the powerswitch.
 10. The ballast by-pass LED tube lamp according to claim 8,wherein the electric shock detection circuit comprises: a pulsegenerating circuit, configured to generate a pulse signal for turning onor off the detection path; and a detection circuit, configured to detecta signal, for indicating the equivalent impedance, on the detectionpath.
 11. The ballast by-pass LED tube lamp according to claim 10,wherein the pulse generating circuit is integrated into the constantcurrent controller.
 12. The ballast by-pass LED tube lamp according toclaim 8, wherein the driving circuit is a non-isolated power converter.13. The ballast by-pass LED tube lamp according to claim 12, wherein thedriving circuit further comprises: a feedback circuit, configured togenerate a feedback signal by sampling a magnitude of current passingthrough the power switch and transmit the feedback signal to theconstant current controller, wherein the constant current controllermodulates, according to the feedback signal, a pulse width of thelighting control signal to maintain the lamp driving signal at apredetermined current value.
 14. A ballast by-pass light-emitting diode(LED) tube lamp, comprising: a lamp tube; two end caps, respectivelydisposed on opposite sides of the lamp tube, wherein each end cap has anexternal connection terminal for receiving an external driving signalhaving a frequency substantially equal to 50 Hz or 60 Hz; a power supplymodule, electrically connected to the external connection terminals andconfigured to generate a lamp driving signal based on the externaldriving signal; and an LED module, disposed in the lamp tube andelectrically connected to the power supply module, for receiving thelamp driving signal, wherein the power supply module comprises: acurrent limiting circuit, electrically connected between at least one ofthe external connection terminals and the LED module, and configured tolimit a current flowing through the external connection terminals andthe LED module to less than a predetermined value when being enabled andto conduct a current above the predetermined value when being disabled;and an electric shock detection circuit, configured to detect a signalon a detection path of the ballast by-pass LED tube lamp and control theenable/disable state of the current limiting circuit according to adetection result, wherein at least some electronic components of thepower supply module are connected via a power circuit board, and thepower circuit board is disposed in at least one of the end caps parallelto an axial direction of the lamp tube.
 15. The ballast by-pass LED tubelamp according to claim 14, wherein the electric shock detection circuitmonitors the signal on the detection path in real time during theballast by-pass LED tube lamp being powered up.
 16. The ballast by-passLED tube lamp according to claim 14, wherein when a current passingthrough the detection path is detected to be less than a referencevalue, the electric shock detection circuit determines the by-pass LEDtube lamp is in an abnormal state, so that the electric shock detectioncircuit enables the current limiting circuit.
 17. The ballast by-passLED tube lamp according to claim 16, wherein the current limitingcircuit is preset to be in the disable state and is switched to theenable state when the abnormal state is determined.
 18. The ballastby-pass LED tube lamp according to claim 16, wherein the currentlimiting circuit is preset to be in the enable state and is maintainedin the enable state when the abnormal state is determined.
 19. Theballast by-pass LED tube lamp according to claim 14, wherein when acurrent passing through the detection path is detected to be greaterthan a reference value, the electric shock detection circuit determinesthe by-pass LED tube lamp is in a normal state, so that the electricshock detection circuit disables the current limiting circuit.
 20. Theballast by-pass LED tube lamp according to claim 19, wherein the currentlimiting circuit is preset to be in the disable state and is maintainedin the disable state when the normal state is determined.
 21. Theballast by-pass LED tube lamp according to claim 19, wherein the currentlimiting circuit is preset to be in the enable state and is switched tothe disable state when the normal state is determined.
 22. The ballastby-pass LED tube lamp according to claim 14, wherein the entiredetection path is part of a current path between the external connectionterminals and including the LED module.
 23. The ballast by-pass LED tubelamp according to claim 14, wherein at least one electronic component onthe detection path is different from electronic components on a currentpath between the external connection terminals and passing through theLED module.
 24. A DC-to-DC power converter with leakage currentprotection, wherein the DC-to-DC power converter has an input side andan output side and comprises: a constant current controller, configuredto generate a lighting control signal having a pulse waveform; a powerswitch, electrically connected to the constant current controller andconfigured to be switched according to the lighting control signal; aconversion circuit, electrically connected to the power switch andconfigured to absorb and release power received from the input side inresponse to the switching state of the power switch so as to generate adriving signal at the output side; a feedback circuit, configured togenerate a feedback signal by sampling a signal on at least one of theinput side and the output side and to transmit the feedback signal tothe constant current controller; and a detection circuit, electricallyconnected to the constant current controller and the input side andconfigured to detect a signal at the input side and generate aninstallation detection signal, wherein: under an installation detectionmode, the constant current controller outputs the lighting controlsignal with at least one first pulse and determines whether to enter anormal driving mode according to the installation detection signal; andunder the normal driving mode, the constant current controller outputsthe lighting control signal with a plurality of second pulses andmodulates the second pulses according to the feedback signal.
 25. TheDC-to-DC power converter according to claim 24, wherein a pulse width ofthe first pulse is less than a minimum pulse width of the second pulse.